In a large, non-stick skillet, slowly MELT butter over medium heat.
ADD brown sugar and cinnamon. STIR continuously until the sugar is dissolved (about 3-4 minutes).
ADD walnuts and continue stirring. ADD up to 2 Tablespoons of water to make a syrup. Stir until bubbling. Remove from heat.
SPREAD the walnuts in a single layer onto a baking sheet lined with parchment paper or a silicone baking mat. SPRINKLE with cinnamon sugar while still warm (optional).
COOL for 1 hour. The walnuts can be stored at room temperature in an airtight container for up to 2 weeks.
