Preheat oven to 325 degrees Fahrenheit. Generously grease a 10-inch bundt pan with cooking spray.
Separate biscuits. Cut biscuits in half and in each half wrap a Reese's cup, pinching the seams to make sure the cups are fully covered. Place wrapped Reese's cups in bundt pan.
In a bowl, whisk together brown sugar and melted butter until combined. Drizzle evenly over balls in bundt pan.
Bake for 40 to 45 minutes, or until the edges are golden brown. Remove from oven and cool for 10 minutes. To remove from bundt pan, gently run a rubber spatula down the edges to loosen. Invert onto a serving platter.
While monkey bread cools, make your peanut butter glaze. Whisk together all the ingredients until smooth. If it's too thick, add a little more milk until the desired consistency is reached.
Drizzle glaze evenly over monkey bread and top with chopped Reese's cups. Serve and enjoy!