Step 1: Prepare dry ingredients

• In a bowl, whisk together flour, baking powder, baking soda, and salt

• Set aside

Step 2: Cream the butter and sugars

• In a large mixing bowl, beat softened butter, peanut butter, brown sugar, and granulated sugar until light and fluffy (about 3 minutes)

• Use a hand or stand mixer on medium speed

Step 3: Add egg and vanilla

• Beat in the egg and vanilla extract until fully incorporated

• Scrape down the sides of the bowl as needed

Step 4: Mix in dry ingredients

• Add the flour mixture gradually to the wet ingredients

• Mix just until combined without overworking the dough

Step 5: Chill the dough

• Cover and refrigerate the dough for at least 30 minutes to firm it up

• This prevents spreading and helps shape retention during baking

Step 6: Shape the cookies

• Preheat oven to 350°F (175°C) and line baking sheets with parchment paper

• Scoop 1 tablespoon of dough and roll into a ball, then shape into a slight oval

• Use the tines of a fork to create the signature crisscross or peanut shell pattern on top

Step 7: Bake the cookies

• Place cookies 2 inches apart on the baking sheet

• Bake for 10–12 minutes or until golden brown around the edges

• Let cool on the sheet for 5 minutes, then transfer to a wire rack to cool completely

Step 8: Make the filling

• In a medium bowl, beat peanut butter and butter until creamy

• Gradually mix in powdered sugar

• Add milk a little at a time until the filling is smooth and spreadable

• Add a pinch of salt if your peanut butter is unsalted

Step 9: Assemble the cookies

• Once cookies are fully cooled, spread a spoonful of filling on the flat side of one cookie

• Press another cookie on top to form a sandwich

• Repeat with remaining cookies