Peanut Butter-filled Chocolate Cookies

Why I Love This Recipe
These are my favorite cookie to make during the holidays, the peanut filling is such a tasty surprise!
Ingredients You'll Need
1-1/2 cups all-purpose flour
1/2 cup unsweetened cocoa powder
1/2 tsp baking soda
1/2 cup butter, softened
1/2 cup granulated sugar
1/2 cup packed brown sugar
1/4 cup peanut butter
1 egg
1 Tbsp milk
1 tsp vanilla
1/2 cup sifted powdered sugar
1/2 cup peanut butter
granulated sugar
Directions
Preheat oven to 350°F.
In a medium bowl sift together flour, cocoa powder and baking soda. Set aside. In a large mixing bowl, beat butter until creamy on low speed. Add sugars and 1/4 cup peanut butter and beat until combined, scraping bowl as needed. Beat in egg, milk and vanilla until combined. Beat in flour. Shape dough into 32 1-inch balls and set aside.
To make the peanut butter filling, mix powdered sugar and 1/2 cup peanut butter until smooth. Shape filling into 32 1/2-inch balls.
To form cookies, slightly flatten each chocolate dough ball, then wrap around the peanut butter filling, sealing completely. Roll the dough between palms to reform into balls.
Place balls 2 inches apart on ungreased cookie sheet. Lightly flatten each with the bottom of a glass dipped in granulated sugar (for the first one, flatten the cookie first, then dip into sugar so it will stick to the bottom of the glass).
Bake 8 minutes or until the surface is slightly cracked and the cookie is just set. Cool for one minute on cookie sheet, then transfer to wire rack and cool completely.
Cookies can be stored in an airtight container, separated with wax paper up to 3 days.