For the Cake

2 1/4 cups cake flour (I used Swan’s Down brand)
1 tablespoon baking powder
1/2 teaspoon kosher salt
1 1/4 cups buttermilk, room temperature
4 large egg whites, room temperature
1 1/2 cups sugar
1 stick (8 tablespoons) unsalted butter, at room temperature
1 teaspoon pure vanilla extract
For the Peanut Butter Buttercream

Ingredients
3 sticks unsalted butter, softened
1 cup creamy peanut butter
2 tablespoons vanilla extract
2 pounds confectioners’ sugar, sifted
6-8 tablespoons heavy cream (if using milk, amount will be less)
For the Filling:

Jelly or Jam in your favorite flavor(s)