In a large skillet, heat the remaining 2 tablespoons of olive oil. Add the scallions and cook over moderate heat until softened, 3 minutes. Add the greens and cook over high heat, stirring, until ...

Stir in the chopped garlic, then after a minute add the tomato purée. Add the tomatoes and the vegetable stock and bring to the boil. Reduce the heat and simmer for 10 minutes.