Position an oven rack in the center and preheat the oven to 350°F. Line baking sheets with parchment paper.

In a large bowl, cream together the softened butter, 1 cup peanut butter, granulated sugar, and packed brown sugar until light and fluffy.

Add eggs one at a time, mixing well after each addition, then add the vanilla extract and mix until smooth.

In another bowl, whisk together the flour, graham cracker crumbs, baking soda, and salt.

Gradually add the dry mixture to the wet ingredients, mixing just until a soft dough forms.

Portion the dough into 1-inch balls and place on prepared baking sheets, flattening slightly.

Bake for 10 to 12 minutes until edges are light golden brown and centers are soft. Cool on baking sheets for 5 minutes, then transfer to a cooling rack.

In a microwave-safe bowl, combine chocolate chips and ¼ cup peanut butter. Microwave in 20-second intervals, stirring until smooth.

Stir in mini marshmallows into the melted mixture and let cool for 5 to 10 minutes until thickened.

Assemble cookies by dolloping filling onto the flat side of half the cookies and topping with the other half. Let set for 30 minutes.