Preheat oven to 350. Grease and flour bundt pan (I use Bakers Joy)
Combine cake mix, carton of sour cream and the 3 eggs until smooth. Pour half of the batter in the prepared pan. Evenly spread halved peanut butter cups over batter. Top with remaining batter.
Bake approximately 40-45 minutes or until toothpick tests done. Allow to cool for 10 minutes and release cake from pan. Cool.
Place chocolate chips, peanut butter and milk in a microwave safe bowl. Microwave in 15 second intervals until chips are melted and mixture is smooth. If mixture is too thick add a little more milk until a glaze consistancy. Pour over cooled cake.