1/4 cup extra-virgin olive oil2 med. onions or leeks, coarsely chopped 6 garlic cloves, chopped 1 Tbsp. cumin seeds 1/2 tsp. dried crushed red pepper 2 lg. bu. mustard greens, coarsely chopped 1 Tbsp. balsamic vinegar
Heat oil in large wide pot over med-high heat. Add onions and sauté until soft, about 7 mins. Stir in garlic, cumin seeds, and crushed red pepper; sauté 3 mins. Add mustard greens to pot in batches (about 1/3 at a time) and stir until each batch begins to wilt before adding next, about 3 mins per batch. Reduce heat to med-low, cover, and cook until greens are very tender, stirring frequently, about 30 mins. Season with salt and pepper. Mix in vinegar. (Can be made 3 hours ahead.) Transfer to bowl and serve hot or at room temperature.
Adapted from Bon Appetit, November 2005