Heat 1 tablespoon of the olive oil in a large casserole. Add the mushrooms, garlic and leek and cook over moderate heat, stirring, until barely softened. Add the stock and tomatoes, season with salt and pepper and bring to a boil. Add the pasta and cook until barely softened, about 4 minutes. Add the wax beans, zucchini and white beans, cover partially and cook until tender. Stir in the peas and basil. Drizzle with the remaining 1 tablespoon of olive oil and serve.