These truly melt in your mouth. You can substitute almond, pistachio or cashew butter and the corresponding nut for the peanut butter and chopped peanuts.

2 cups all-purpose flour
1 teaspoon baking powder
1/2 teaspoon baking soda
1/4 teaspoon salt
7/8 cup (1 3/4 sticks) unsalted butter, softened
1/2 cup creamy peanut butter
1 cup confectioners sugar, sifted
1/2 cup firmly packed light brown sugar
1 1/2 teaspoons vanilla extract
1 egg
1/2 cup coarsely chopped peanuts

In a large bowl, combine flour, baking powder, baking soda and salt; set aside.

In a large mixing bowl with electric mixer on medium speed, beat butter and peanut butter until light and fluffy. Add confectioners' sugar and brown sugar; beat on medium speed until smooth. Beat in vanilla extract and egg. With mixer on low speed, gradually beat in reserved flour mixture. Fold in peanuts by hand. Form dough into 1 1/4-inch balls. Place balls, 2 inches apart, on baking sheet lined with parchment paper. Using your lightly floured palm, flatten each ball into a disk about 1 1/2 inches in diameter. Bake in a 350 degree F oven about 10 minutes or until edges are lightly browned. Let cookies cool slightly on baking sheet, then use a spatula to transfer cookies to a wire rack; let cool completely. Cookies can be stored in an airtight container up to one week.