Cupcakes:

1/2 cup unsalted butter

3/4 cup packed light brown sugar

1/2 cup unsweetened cocoa powder

1 Tablespoon vanilla extract

2 large eggs

1/4 teaspoon salt

1/2 teaspoon baking powder

2/3 cup all-purpose flour

Peanut Butter Frosting:

5 Tablespoons unsalted butter, softened

1 cup creamy peanut butter

1 cup confectioners’ sugar

1/3 cup heavy cream

1 teaspoon vanilla extract

¼ teaspoon salt

Chocolate sprinkles

Preheat the oven to 375°. Line a muffin pan with cupcake liners.  Melt butter in the microwave in a large microwave safe bowl. Mix in the sugar until smooth and microwave for about 1 minute. Stir the mixture until smooth again. Whisk in the vanilla and eggs. In a separate bowl, mix together the salt, baking powder, cocoa powder, and flour. Slowly add to the wet ingredients and stir until completely combined.  Fill the muffin tins about 2/3 full. Bake in the prepared muffin tin for about 8-10 minutes). Allow to cool completely.  Beat softened butter on medium speed for 1 minute until completely smooth and creamy. Add the peanut butter and beat on medium-high speed until the two are combined. Add the confectioners’ sugar, cream, vanilla extract, and salt. Beat on low speed for about 20 seconds, then gradually increase to high speed. Beat on high for 1 minute. Frost cooled cupcakes. Top with chocolate sprinkles, if desired.