Preheat the oven to 350℉/177℃. Grease and parchment line two 8-inch round cake pans and set aside.
In a large bowl, whisk together the flour, sugar, cocoa powder, baking soda, baking powder and salt.
2 cups all-purpose flour, 2 cups granulated sugar, ¾ cup dutch-processed cocoa powder, 1½ teaspoons baking soda, 1 teaspoon baking powder, 1 teaspoon kosher salt
In a separate bowl, whisk together the eggs and egg yolks, oil, butter, sour cream and milk until smooth, then add to the dry ingredients and mix until incorporated.
2 large eggs, 2 large egg yolks, ½ cup vegetable oil, ½ cup unsalted butter, ¾ cup sour cream (full fat), ¼ cup whole milk
Next, add in about ⅓ of the hot coffee and quickly stir to temper the mixture. Add in the remaining coffee and mix until fully combined, careful not to over mix (or slosh it over the sides).
1 cup very hot coffee or water
Divide the batter evenly between the two pans and bake on the middle rack for 30-35 minutes or until a toothpick inserted in the center comes out clean. Cool on a wire rack for 10 minutes, then remove the cakes from the pans, take off the parchment layer, and finish cooling on the racks.
Once cool, wrap each cake layer in plastic wrap and transfer to the fridge for an hour. This will firm up your cake which will help when it’s time to frost and assemble!