Peanut Butter Blondies

With an electric mixer, beat butter and peanut butter until fluffy. Add sugar and light-brown sugar and beat until combined. Add eggs, one at a time, beating after each addition. Add vanilla and mix until smooth. In a separate bowl, stir together flour, baking powder, and salt. Gradually add the dry ingredients to the peanut butter mixture, beating after each addition, until a smooth dough forms. Spread batter in an 8-inch baking dish coated with cooking spray and sprinkle with chopped peanuts. Bake at 350° until a toothpick inserted in the center comes out clean (30–35 minutes). Cool blondies on a wire rack for 15 minutes, then cut into 12 rectangles and serve. (The blondies will keep for 3 to 4 days in an airtight container.)