1/2 teaspoon baking soda
1/4 teaspoon baking powder
1/2 teaspoon salt
1/2 cup (1 stick) unsalted butter, melted
1 cup granulated sugar
2 egg whites
1/4 cup sour cream (or vanilla yogurt)
3/4 cup milk
2 1/2 teaspoons vanilla extract
Seeds scraped from 1/2 a split vanilla bean
12-15 peanut butter cups
1/4 cup shortening
1/2 cup creamy peanut butter
1 teaspoon vanilla extract
1/4 - 1/2 cup heavy whipping cream (or milk)
4-5 cups powdered sugar
Prep. Preheat the oven to 350 degrees. Line a muffin tin with 12 cupcake liners and set aside.
Mix dry ingredients. In a medium bowl, whisk together the flour, baking soda, baking powder, and salt. Set aside.
Melt. Melt the butter in the microwave in a large bowl. Stir in the sugar until combined. Stir in the egg whites, sour cream, milk, and vanilla extract.
So... what do I do with this vanilla bean? Using a sharp knife, cut one vanilla bean in half length-wise, from top to bottom. Set aside one half for later (store in an airtight container). Use a knife or spoon to gently scrape all the black seeds from the other half into your butter mixture (it'll look like wet black sand). Be sure to break up any clumps with your spoon or spatula.
What if I don't have vanilla beans? No big deal. You can substitute the vanilla bean with 1 teaspoon vanilla powder or 1 teaspoon vanilla bean paste or 3/4 teaspoon ground vanilla beans or 1-2 teaspoons vanilla extract.
Make your cupcake batter. Slowly mix the dry ingredients into the wet ingredients until smooth and no lumps remain.
Scoop. Fill cupcake liners halfway with batter (tip: use a cookie scoop!). Place a peanut butter cup in the center of each, then place another scoop of cupcake batter over the top to cover the peanut butter cup completely.
Bake. Bake for 20 minutes, or until a toothpick inserted into the cake tests clean. Remove from oven and allow to cool completely before frosting.
Frost. To make the frosting, combine softened butter, shortening, peanut butter, and vanilla extract in the bowl of an electric mixer until smooth. Add in four cups of powdered sugar. Add 1/4 cup of the whipping cream, mix until combined well, then beat on high speed until fluffy. Continue adding the remaining powdered sugar and whipping cream until the frosting is the consistency you want... then frost your cupcakes!
Makes 12-15 cupcakes.