1/2 cup melted butter
2 tablespoons white sugar
1 egg
1 teaspoon vanilla extract
1/2 cup milk
1 1/2 cups all-purpose flour
1 teaspoon baking powder
1 teaspoon baking soda
1 cup peanut butter
1/2 cup peanut butter
3 tablespoons butter, melted
1 teaspoon melted butter
1/2 cup peanut butter
Preheat the oven to 350 degrees F (175 degrees C). Line cookie sheets with parchment paper.
In a medium bowl, cream together the melted butter, white sugar, egg and vanilla until smooth. Mix in the milk and flour. Stir in the peanut butter, flour mixture. Stir in the peanut butter, peanut butter mixture until just blended. Drop by rounded spoonfuls onto the prepared cookie sheets.
Bake for 8 to 10 minutes in the preheated oven. Allow cookies to cool on baking sheet for 5 minutes before removing to a wire rack to cool completely.
To make the icing and filling: Beat 3 tablespoons butter and 3 tablespoons peanut butter together in a medium bowl until smooth. Beat in the peanut butter and peanut butter mixture.