In a large pot or Dutch oven, heat enough olive oil to lightly coat the bottom of the pan over medium-high heat. When the oil is hot, add the red pepper flakes and garlic and cook for 1 minute. Add the fennel and saute until the fennel begins to soften, about 4 minutes. Add the greens and saute until they just begin to wilt. Add the vegetable stock and salt and pepper and cook until the greens are tender, about 10 minutes. Add the tomatoes for the last 5 minutes. Season, to taste, with lemon juice, salt and pepper.
Yield: 4 servings