Ingredients:

• 2 cups all purpose flour
• 2 teaspoons baking powder
• 4 teaspoons baking soda
• 1 pound (4 sticks) butter, at room temperature
• 2/3 cup creamy peanut butter
• 1 cup granulated sugar
• 1 cup firmly packed light brown sugar
• 2 large eggs
• 1.5 teaspoons vanilla extract
• 1/3 cup coarsely chopped peanuts
• 2.5 cups quick-cooking oats

For the filling:

• 1/4 pound (1 stick) butter, at room temperature
• 1/2 cup creamy peanut butter
• 1- 2/3 cups confectioners' sugar

Instructions:

For cookie dough:  Preheat oven to 350 degrees.  In a bowl, mix together the flour, baking powder and baking soda; set aside.  Using a mixer with a paddle attachment, cream together the butter and peanut butter.  Add sugars and beat at medium speed for 4 minutes, scraping down bowl twice.

At low speed, add eggs and vanilla.  Add flour mixture and beat at low speed until well mixed, frequently scraping down bowl.  Add peanuts and oats, and mix well.  Using an ice cream scoop 2 inches in diameter, place balls of dough on parchment lined baking sheets at least three inches apart.  Bake until cookies have spread and turned very light golden brown, about 10 minutes.  Remove from oven and set aside to cool and firm up, 5 to 10 minutes.  Transfer to a rack to cool completely before filling.

For filling:  using an electric mixer, cream together the butter, peanut butter and confectioners' sugar until very smooth.

To assemble cookies, spread a thin layer (about 1/8 inch) on underside of a cookie.  Sandwich with another cookie.  Repeat.

Yield:  24 large cookies.

tip:  Measuring peanut butter in a regular measuring cup can be difficult, messy and not very accurate.  To make the job easier, purchase one of these Wonder Plunger measuring cups that are designed for difficult to measure ingredients, like honey or molasses.  When you push up the bottom of the cup, the peanut butter comes right out, cleanly and accurately.