Preheat the oven. Preheat to 350°F and generously grease a 12-cup Bundt pan with butter.
Coat the biscuits. Cut each biscuit into 4 pieces. Combine the granulated sugar and cinnamon in a large bowl or zip-top bag. Toss the biscuit pieces until evenly coated, then arrange them in the prepared Bundt pan.
Make the butter sauce. In a small saucepan over medium-low heat, combine the butter, brown sugar, and ½ cup of the remaining cinnamon-sugar mixture. Heat until the butter melts and the mixture just begins to bubble. Remove from the heat and stir until the sugars dissolve.
Add the sauce. Pour the warm butter mixture evenly over the biscuit pieces.
Bake. Bake for about 30 minutes, or until golden brown and cooked through. If the top browns too quickly, loosely cover with foil.
Cool and serve. Let the monkey bread rest in the pan for 5 minutes, then carefully invert onto a large serving plate. Serve warm.