Heat oil in a stockpot and sauté onion over medium heat for about 5-7 minutes, until tender. Add garlic and red pepper flakes (use larger amount if you tend to like things spicier) and sauté for another minute.
Add brown sugar, mustard greens and water. Slice sausage in quarters, lengthwise, and then slice thinly. (Use the larger amount of sausage if you want a really meaty dish.) Add sausage to pot.
Heat to boiling, stir greens down, cover, reduce heat to lowest, and boil gently for about 45 minutes, stirring once or twice.
Uncover and serve. It will be juicy.
Recipe by Cut 'N Clean Greens
Photo by Maryam Nikkhah, VC Foto