Oatmeal Peanut Butter Sandwich Cookies

Preheat the oven to 350 degrees. Begin by creaming the butter and sugars for the cookies. Beat in the egg and vanilla. In a small bowl mix together your flour, baking soda, baking powder, and salt. Mix into the creamed butter and sugars. Mix in the oats and stir until combined. Drop teaspoonfuls (or use a small cookie scoop) of dough onto a parchment-lined baking sheet. Make a criss cross pattern with a fork to flatten the cookies. Bake for 10 minutes and allow to cool.

To make the filling, beat all filling ingredients together until well-mixed and smooth. Spread the filling on the bottom of one cookie and top with another to form a sandwich. Repeat with all the cookies.

(Recipe from Joanne Reaney. See the related blog post for more details.)