Boil yams into water until fork tender. Drain and let cool.
Peel yams and cut into chunks.
Melt butter in a skillet and add 1/2 cup brown sugar. Let cook for about 3 minutes over high heat.
Add yams and sprinkle with remaining 1/4-1/2 cup brown sugar. Reduce heat to simmer and sprinkle with 2 Tbsp water. Turn occasionally to coat evenly. Sprinkle with cinnamon if desired.
Cover and let cook until sugar thickens and yams are sticky. Makes 4 servings. Enjoy!