Preheat oven to 350 degrees F.

Cookies: In a small bowl combine flour, baking powder, baking soda and oats. Set aside.

Cream the butter and peanut butter together in a stand or handheld mixer on high. Add sugar, brown sugar and vanilla. Continue to beat until mixture is fluffy. Add the egg and beat until combined.

Slowly add the dry ingredients and mix until incorporated.

Roll batter into 1-inch balls and use a lightly floured fork to flatten lightly. Make sure to leave about 2 inches between each cookie as they will spread a little.

Bake 10-12 minutes, or until lightly golden. Cool on a wire rack.

Filling: Using your mixer, cream butter and peanut butter together. Add the powdered sugar and mix on high. Gradually add the cream until mixture is really thick and smooth. Set aside until later.

When cookies are cool enough to handle, match each cookie halves with similar sized partners.

Place a scoop of filling inside and use the other cookie to smash it to the edges.

Do this to remaining cookies and enjoy!