Preheat oven to 350°F (175°C). Line baking sheets with parchment paper.

In a large bowl, cream together butter, peanut butter, granulated sugar, and brown sugar until light and fluffy.

Beat in eggs one at a time, then mix in vanilla extract.

In a separate bowl, whisk together flour, baking soda, and salt. Gradually add to wet mixture.

Roll dough into small logs or balls and create ridged patterns with a fork. Place on baking sheets.

Bake 10–12 minutes or until lightly golden. Cool completely on wire racks.

For filling, beat peanut butter and butter until smooth. Gradually add powdered sugar and vanilla until fluffy.

Spread filling on one cookie and sandwich with another.