2 teaspoons olive oil
2 cups thinly sliced onion
8 cups torn Swiss chard leaves (about 12 ounces)
1 teaspoon Worcestershire sauce
1/4 teaspoon salt
1/8 teaspoon black pepper

Heat oil in a large nonstick skillet over medium-high heat. Add onion; sauté 5 minutes or until lightly browned. Add chard; stir-fry 10 minutes or until wilted. Stir in Worcestershire, salt, and pepper.