Ingredients:

For the cookies:

1/2 cup butter, at room temperature

1/2 cup shortening

1 cup brown sugar

3/4 cup granulated sugar

1 cup peanut butter

2 eggs

1 tsp vanilla extract

1 1/2 cups flour

2 tsps baking soda

1 tsp kosher salt

1 1/2 cups oats (quick or old fashioned)

For the frosting:

4 tbsp butter, at room temperature

1/2 cup creamy peanut butter

1 cup powdered sugar

2 tbsp milk or cream

1 tsp vanilla

Preparation:

Beat together butter & shortening for 2 minutes, scraping sides & bottom.

Add brown sugar & granulated sugar. Beat for 2 minutes, until light & fluffy, scraping the sides & bottom. Add 1 cup peanut butter & beat until incorporated. Add eggs & vanilla extract, beat well.

Add flour, baking soda, & salt, stir together until mostly combined. Add oats & stir until combined, scraping bottom & sides, & careful not to over mix. Cover the bowl & chill for a minimum of 3 hours or overnight.

Preheat oven to 350 degrees. Scoop out 1 or 2 inch, depending on preferred size. Bake for 8-10 minutes, ensuring middle is cooked, but careful not to over bake. Allow to cool on sheet for 5 minutes before transferring to a cooling rack. Cool completely before frosting.

Prepare the frosting. Beat butter & peanut butter together until smooth & creamy. Add powdered sugar & beat until well incorporated. Add milk, cream, & vanilla extract. Add more milk/ cream, if desired.

Spread frosting on bottom of cookie & sandwich with another.

Source: https://thefoodcharlatan.com/peanut-butter-sandwich-cookies/