Step 1

Preheat oven to 350 degrees.

Step 2

In a large mixing bowl, beat butter with sugars and peanut butter until creamy and well combined. Add milk and vanilla until blended. Add eggs and beat until combined. Beat in flour, salt, baking soda, and cornstarch just until blended. Fold in peanut butter morsels.

Step 3

Drop 2 tablespoons of cookie dough onto parchment paper lined cookie sheet. Flatten with fork. Chop each peanut butter cup into fourths and press into tops of cookies.

Step 4

Bake for 11-13 minutes. Allow to cool 2 minutes on pan, transfer to wire rack and cool completely.