Quick Collard Greens

Heat a Dutch oven over medium-high heat. When hot, add olive oil and yellow onion; season with salt and black pepper. Cook for 4 minutes or until onions are translucent; add garlic and crushed red pepper and cook for another minute. Add collard greens, in batches if necessary, alternating with chicken broth, and cook, stirring frequently, until they begin to wilt. Bring to a simmer; cook greens for 12 to 14 minutes or until they are tender and most of the liquid has evaporated. Stir in vinegar and butter, if desired. Serve hot.