Preheat your oven to 350°F (175°C). Cream together the softened butter, granulated sugar, and brown sugar until light and fluffy, about 3 minutes.

Add the egg and vanilla extract, mixing until combined. Whisk together flour and baking powder in a separate bowl, then blend into wet ingredients until a cohesive dough forms.

Drop mounds of dough onto a parchment-lined baking sheet, spaced about 2 inches apart. Bake for 10-12 minutes until edges are golden and centers remain soft.

Remove cookies from the oven and cool on a wire rack for about 10 minutes.

Soften peanut butter ice cream at room temperature for 5-10 minutes until easy to scoop.

Turn half the cookies flat side up, scoop peanut butter ice cream onto each, and press another cookie on top to create a sandwich.

Freeze assembled sandwiches for at least 30 minutes to firm up the ice cream.

Remove from freezer, let sit for a few minutes before serving for enhanced flavors.