Preheat oven to 350℉. Grease a bundt pan or spray with cooking spray.
In a bowl stir together brown sugar and melted butter until well combined. Set aside.
Mix together cinnamon and sugar in a large bowl. Cut biscuits into quarters, add to sugar mixture, and toss to coat. Shake off any excess sugar.
Layer the sugared biscuits and walnuts in the prepared bundt pan. Drizzle the brown sugar mixture evenly over the top.
Bake for 33-37 minutes or until golden and no longer doughy in the center. Allow to cool in pan for 5 minutes. Loosen edges with a spatula and invert onto a serving platter. Serve warm.
Notes
Store leftovers in an airtight container at room temperature for up to 3 days. Or freeze cooled monkey bread whole or in individual portions in a zippered bag, or wrapped in plastic and then foil, for up to 3 months.