Steak Crostini with Horseradish Cream

Assembled piece of steak crostini on a board.

5 from 3 votes

Steak Crostini with Horseradish Cream

Steak crostini are the perfect appetizer for happy hours, cocktail parties, or any holiday gatherings! These easy mini baguette appetizers are topped with grilled, marinated flank steak, horseradish cream, and caramelized onions.

Prep Time1

Cook Time1

Total Time2

Course: Appetizer, Snack

Cuisine: American

Servings:

Calories: 266kcal

Author: Callan Wenner

Equipment

Large frying pan
Mixing bowls
Whisk
Grill, cast iron pan, or sheet pan
Digital kitchen thermometer

Ingredients

Steak Marinade

1-1½ lbs hanger steak skirt steak, or flank steak
⅓ cup soy sauce
¼ cup extra virgin olive oil
2 tablespoons sugar brown or granulated
1 tablespoon apple cider vinegar or balsamic vinegar
½ tablespoon dijon mustard
1 large garlic clove minced

Caramelized Onions

3 large yellow onions
2 tablespoons extra virgin olive oil

Horseradish Cream

½ cup sour cream
½ cup mayonnaise
2-4 tablespoons prepared horseradish
1 tablespoon apple cider vinegar
½ teaspoon kosher salt
¼ teaspoon cracked black pepper

Toasts

1 baguette sliced into ½” pieces (about 20-24 slices)
¼ cup extra virgin olive oil
1 large garlic clove
fresh chives finely chopped, for garnish
flaky sea salt for garnish

Instructions

Mix together the ingredients for the marinade. Add the steak to a gallon ziptop bag or a dish and pour the marinade overtop. Marinate in the fridge for at least 4 hours, or up to 24 hours.
1-1½ lbs hanger steak, ⅓ cup soy sauce, ¼ cup extra virgin olive oil, 2 tablespoons sugar, 1 tablespoon apple cider vinegar or balsamic vinegar, ½ tablespoon dijon mustard, 1 large garlic clove
Peel, half, and slice the onions very thinly.
3 large yellow onions
Heat a large skillet over medium-low heat. Add the olive oil and onions and toss to coat. Allow the onions to cook for 5 minutes, toss again, then turn the heat to the lowest setting.
2 tablespoons extra virgin olive oil
Continue cooking the onions for 30-40 minutes, stirring every 5 minutes or so, until the onions are golden brown and turn almost jammy-looking. Once cooked, remove from the heat to cool completely.
Note: If the onions are burning at any point, add ¼ cup of water to loosen any browned bits from the bottom of the pan. The water will evaporate during the remaining cooking process.
Whisk together all ingredients for the horseradish cream. Taste for seasoning and add more salt as necessary. Cover and store in the fridge for up to 2 days.
½ cup sour cream, ½ cup mayonnaise, 2-4 tablespoons prepared horseradish, 1 tablespoon apple cider vinegar, ½ teaspoon kosher salt, ¼ teaspoon cracked black pepper
Remove the steak from the fridge and let it come to temperature for one hour prior to cooking. Also remove the caramelized onions and horseradish cream so the chill can come off.
During this time, slice the baguette into ½” slices on the bias, and add to a baking sheet. Brush olive oil onto the tops of all slices, then broil until golden (watch the pieces the whole time).
1 baguette, ¼ cup extra virgin olive oil
Remove from the oven and turn each piece over, then finish broiling until the second side is golden. Cut off the very tip of a peeled garlic clove and rub the cut side of the clove on every piece of toast.
1 large garlic clove
Remove the steak from the marinade and pat dry with paper towels (this will help get a nice, browned crust on the meat).
Heat a large cast iron skillet or grill on medium high heat until very hot.
Coat the pan with olive oil, then add the steak. Cook for 2-3 minutes (don’t move it), then flip and cook an additional 2-3 minutes. Continue flipping until your preferred internal temperature is reached (note it will rise another 5-10 degrees during rest time).
Note: Rare is 120℉, medium rare is 130℉, medium is 140℉. I don’t suggest cooking this cut of meat past medium.
Rest the steak on a cutting board for 10-15 minutes, then slice the steak into very thin strips (no thicker than ¼”) against the grain, at a 45-degree angle.
*Add the toasts to a platter, then add caramelized onions, steak, and horseradish cream to each crostini. Finish with chopped fresh chives and flaky sea salt.
fresh chives, flaky sea salt

Video

Notes

*If you don't want to assemble all of the crostini individually, place all of the components on a large board or platter, adding the onions, horseradish cream, and chives to bowls and allow people to build their own toasts.

Store leftover baguette slices in a zip top bag and re-toast when serving again. All other ingredients should be stored in the fridge for up to four days.

Nutrition