Sweet, caramelized Purple Sweet Potato Pie uses brown butter to add a delicious nuttiness to the warm-spiced filling. Nested in a flaky pie crust and piled with meringue toasted to marshmallow goodness.
Posted: 10/13/2020; Updated: 10/26/2021
First, allow me to re-mention the addition of brown butter in the sweet potato filling which gives the pie a little something extra that you can’t quite put your finger on, but you KNOW it’s there.
Also, the brown sugar in the filling provides a rich caramel flavor and the addition of the warm spices make it feel like autumn in your mouth!
This southern classic is thick and dense, yet oh so creamy and leaves you going back for just one more bite. I will never tire of this pie. Or pies or tarts in general. Pastry is life.
This recipe is made with my all-butter pie crust – take a look through before getting started. It has all the tips and tricks you’ll need to master a homemade, super flaky pie crust!
What are Purple Sweet Potatoes
Purple Sweet Potatoes, also known as an Okinawan Sweet Potatoes, Hawaiian Sweet Potatoes, Japanese Sweet Potatoes, or Purple Yams have a beautiful purple flesh and light to medium brown skin. They are creamy and have a better depth of flavor than orange sweet potatoes, and taste more of honey! They are also incredibly vibrant – though the brightness inside each potato can vary.
While they are sometimes called purple yams, they are not a yam. Yams are drier and have a higher starch content. While all names and versions are similar, you should be looking for either Okinawan, Japanese, or Hawaiian Sweet Potatoes.
When purchasing, be careful not to be tricked by a purple-skinned sweet potato, which actually has a yellow/white flesh. You want brown skin and purple flesh! My local, favorite Asian market carries Purple Sweet Potatoes, but I have also found them at Trader Joe’s and Whole Foods from time to time.
My suggestion would be to call ahead to a few stores to see if they carry them instead of going on a wild goose chase. If you can’t find purple sweet potatoes in your area, you can absolutely make this with normal orange sweet potatoes.
Ingredients & Tools
- Purple sweet potatoes. We talked about this just above, but start calling around to figure out who has the goods!
- Unsalted butter. You’ll need this in two forms: 1) freezing cold for the pie crust, and 2) cooked down into brown butter, which is a non-negotiable here! Check out my How to Brown Butter post for all the tips on how to do this and how long to cook it for.
- Heavy whipping cream and milk. Both are needed here.
- Eggs. Two whole for the filling and three whites for the meringue.
- Sugars. Light brown for the sweet potato filling, granulated for the Swiss meringue.
- Spices. Ground cinnamon, nutmeg, ginger. This is a sweet potato pie, after all.
- Vanilla paste or extract. Just get the vanilla paste. Especially for meringue, it’s really the second best option to real vanilla beans (which are expensive).
- Food processor or pastry cutter. This is for the pie dough, I pretty much always use my food processor for my crust recipe.
- Pie weights or dried rice or beans. This is necessary to par-bake the crust and prevent the sides from slouching. Do not eat the rice or beans after using – these are now your new pie weights (store in a bag or container). If you you don’t have any of these items, add a piece of parchment paper over the crust and place another pie dish on top.
How to make the Purple Sweet Potato Pie
STEP 1: Make the All-Butter Pie Crust . Be sure that your butter is super cold and don’t over blend it. Visit the post write up for all the details on how to do this. Hydrate the dough in the fridge for 2 hours.
STEP 2: While the crust is hydrating, wash and pierce 4-5 purple sweet potatoes and bake in a 400℉ oven for about one hour or until the flesh is very soft. Remove from the oven, slice open to cool, then scoop out the flesh and mash diligently with a fork until completely blended. You can also pass this through a ricer or sieve to get rid of any fibrous pieces, but that is optional.
STEP 3: Once the dough is hydrated, remove it from the fridge to stand at room temperature for 15 minutes. Lightly flour your work surface and roll out the dough until it’s about 1/8” – 1/4” thick. Transfer to the pie dish, trim and crimp.
Freeze the crust for 15 minutes, dock all over with a fork, then fill with parchment paper and pie weights and bake in a 375℉ oven for 20 minutes. Remove the weights and bake for another 10-15 minutes, then remove to a wire rack to cool.
Sweet Potato Filling
STEP 4: While the crust is baking, make the brown butter and transfer to a heatproof bowl. Follow my How to Brown Butter post for tips on how to do this.
STEP 5: Combine the mashed purple sweet potato, brown butter, heavy cream, milk, brown sugar, beaten eggs, cinnamon, nutmeg, ginger, salt, and vanilla in a large bowl with a whisk until fully combined.
Pour into the prepared pie crust and bake for 40-50 minutes or until the pie is set. It will look slightly puffy on the edges and may still have a slightly jiggle in the center, but it should not be sloshy.
Cool at room temperature for 2 hours, then transfer to the fridge for 2 hours to finish cooling and setting.
STEP 6: Once the pie is completely chilled, remove it from the fridge to come back to temperature as you begin making the Swiss meringue topping.
This soft meringue topping is made with the Swiss method, which means the egg whites are first cooked with sugar before whipping. Because this method stabilizes the whites, no cream of tartar is needed for this meringue. It’s also a much smoother, silkier texture and also doesn’t require baking.
STEP 1: Start by separating the yolks from the whites. Don’t get any yolks in the whites or you’ll have to start over (it won’t whip up properly). Then, prepare a double boiler by filling a saucepan with about 2 inches of water and turn to high heat. Add a heat proof bowl over top that fits securely. You don’t want any of the water touching the bottom of the bowl.
STEP 2: To the bowl, add the egg whites, sugar, and salt and whisk to combine. Continue lightly whisking until the mixture is rather warm and the sugar granules have dissolved. Check this by rubbing your fingers together in the mixture. If you can still feel sugar granules, continue cooking. It will be rather warm to the touch, but not overly hot.
Whipping the meringue
STEP 3: One the mixture is ready, add it to the bowl of a stand mixer fitted with the whisk attachment and whip on medium speed for about a minute. Turn to high speed and whip until stiff peaks form and the meringue gets caught in the middle of the whisk. The peak of the meringue should stand up to a point when you pull the whisk out. Once the meringue hits stiff peaks, add the vanilla then mix on high speed once more to combine.
Add all of the meringue to the middle of the pie and keep as much height as possible in the center. Use the mouth of a large spoon to dip it into the meringue, then pull up and twist to get nice swoops and peaks.
STEP 4: Use a kitchen torch to toast the meringue. This is really the best and most reliable method. If you don’t have a torch, carefully broil in the oven, turning the pie to brown it as evenly as possible.
Storing and Freezing
Store the pie in the fridge for three days. I like to cover any exposed sides after slicing with plastic wrap, but otherwise, it doesn’t need to be covered. Bring the slices or pie to room temperature before eating.
To freeze, wrap the cooked pie in plastic wrap and foil and freeze for one month. Thaw uncovered in the fridge, bring to room temperature, then prepare and add the meringue.
- In my tests, the color came out differently each time, depending on how bright the flesh was in each potato. If yours is lacking a bit of color, simply add a touch of ube powder or purple food coloring to help her shine bright.
- I prefer to pass my sweet potatoes through a sieve. I’ve found that Japanese purple sweet potatoes are a bit stringier so the texture of the pie benefits the removal of any fibrous pieces.
- Add your pie to the lower third of the oven for the final 15 minutes. This helps to ensure the bottom of the crust is fully baked.
Other Recipes to Try
- Banoffee Cream Pie
- Peach Frangipane Galette (you can make this with pears!)
- Cinnamon Panna Cotta Tart
- Chocolate Espresso Tart
Pin for Later
Purple Sweet Potato Pie
- Food processor or pastry cutter
- Rolling Pin
- Pie weights or dried rice or beans
- Parchment paper
- 9 inch pie dish
- Stand mixer with whisk attachment, or handheld mixer
Flaky Pie Crust
- 3¼ cups all-purpose flour 390g
- 1 cup + 6 tablespoons unsalted butter cold and cubed (311g)
- 1 tsp salt
- ⅔ cup water with ice (150ml)
Sweet Potato Filling
- 1 cup purple sweet potato mashed (about 4-5 purple sweet potatoes)
- ½ cup + 2 tablespoons unsalted butter browned and in a liquid state (113g)
- ½ cup heavy whipping cream 119g
- ¼ cup whole milk 152g
- ¾ cup light brown sugar 150g
- 2 large eggs room temperature and beaten
- ½ teaspoon ground cinnamon
- ½ teaspoon ground nutmeg
- ¼ teaspoon ground ginger
- ¼ teaspoon kosher salt
- 1 teaspoon vanilla paste or extract
- Egg whites from 3 large eggs
- ¾ cup granulated sugar 150g
- ⅛ teaspoon salt
- 1 teaspoon vanilla paste or extract
- Cut the butter into 1/2" cubes and place in the freezer. In a bowl, add the water and some ice cubes and set aside. Using a food processor, add the flour and salt to the bowl and pulse once to combile. Add the chilled butter evenly around the flour.
- Pulse the mixture until the butter reaches pea-sized pieces and looks crumbly. Add in the ⅔ cup ice cold water (not adding the ice cubes), and pulse again until the dough starts to form a ball (you want to still see butter chunks). If you don't have a stand mixer, use a pastry cutter or two sharp knives to cut the butter into the flour, then add the water and continue cutting until it comes together.
- Remove the dough, separate into two even pieces (weighing recommended), then flatten into one-inch discs and wrap each piece of dough in plastic wrap. Place in the fridge for 1-2 hours to hydrate. Only one disc of dough is needed for the pie – freeze the other in a ziptop bag for 3-4 months.
- Once properly chilled, remove one disc of dough from the fridge and wait about 15 minutes for the dough to slightly come to temperature. This will help you roll out your dough without it cracking. Lightly flour a rolling pin and work surface, then roll out the dough until it’s about ⅛ inch thick and is at least 2 inches wider than your pie dish. Continue to lightly flour your surface and pin if the dough begins to stick.
- Carefully transfer your dough to your pie dish, pressing it into place on the bottom and sides and trim and crimp the edges any way you’d like. Place into the freezer for 15 minutes. At this point, preheat your oven to 375℉/190℃.
- Remove from the freezer and dock the bottom of the dough all over with a fork. Line the pie with parchment paper or aluminum foil and completely fill with pie weights (or dried beans or rice, but do not use to eat afterwards). The weights should come the whole way to the top of the pie crust. Gently press down and into the sides so the weight is fully distributed.
- Bake the crust for 20 minutes, then remove the pie weights and parchment and bake for another 10-15 minutes. Remove the pie from the oven and place on a wire rack to cool completely.
Sweet Potato Filling
- Dock the top of the sweet potatoes a few times with a fork then bake at 375℉/190℃ for about an hour until soft and tender. When the potatoes are almost done in the oven, make the brown butter.
- Over medium heat, add the unsalted butter into a saucepan and allow to melt and bubble. Swirl occasionally until you see that the milk solids on the bottom of the pan have started to become golden brown. It will also start to become incredibly fragrant and nutty. Once ready, pour the butter into a heat proof bowl and set aside.
- Remove the potatoes from the oven and allow to cool until you are able to handle them. Scoop all flesh out of the skins and using a potato ricer or a fork, mash the sweet potatoes until they are as smooth as you can get them. You can also pass them through a sieve to get a super smooth consistency.
- Once the potatoes are ready, combine the mashed sweet potatoes, brown butter, heavy cream, milk, brown sugar, beaten eggs, cinnamon, nutmeg, ginger, salt and vanilla into a large bowl and whisk until completely combined.
- Pour the mixture into your cooled crust and smooth out the top. Bake at 350℉/177℃ for about 40-50 minutes until it’s set. You may need to add a ring of foil to the edges of your crust if they start to turn too brown. The pie will have a slight jiggle in the center (but not sloshy) will look a bit puffy on the sides.
- Remove the pie to a wire rack to cool for 2 hours, then place in the fridge for 2 more hours before making the meringue topping. If you add the meringue before it is completely cool, it will melt and ooze off.
- Fill a saucepan with about two inches of water and turn to high heat. Add a heat proof bowl over top that fits securely. You don’t want any of the water touching the bottom of the bowl.
- To the bowl, add the egg whites, sugar, and salt and whisk to combine. Continue lightly whisking until the mixture is rather warm and the sugar granules have dissolved. Check this by rubbing your fingers together in the mixture. If you can still feel sugar granules, continue cooking.
- One the mixture is ready, add it to the bowl of a stand mixer fitted with the whisk attachment and whip on medium speed for about a minute. Add the vanilla, then turn to high speed and whip until stiff peaks form and the meringue gets caught in the middle of the whisk. The peak of the meringue should stand up to a point when you pull the whisk out.
- Add all of the meringue to the center of the pie, and add swoops using a spoon or spatula. Use a blow torch to brown the meringue to your liking. You can also pop it into the oven under high broil to get a bit of browning, but a torch it a much easier way to get even coverage.