To prepare a swirled peanut butter cup brownies recipe, first you need to prepare the brownie batter. First, you'll need the following ingredients: 1 1/2 cups semi-sweet chocolate chips 2 tablespoons unsalted butter 1 tablespoon vanilla extract 1 teaspoon kosher salt 1/2 teaspoon baking powder 1/8 teaspoon salt Instructions Preheat the oven to 350 degrees F. Line two 8-inch square pans with foil and set aside. Cream the butter and sugar until light and fluffy. Add the vanilla and beat until smooth. Stir in the flour and salt. Pour the wet ingredients into the dry ingredients and mix until just combined. Spread the batter evenly over the foil-lined pan. Bake for 20 to 25 minutes or until the edges are set and the center is set. Allow to cool before cutting into squares.