This recipe has a flavor profile very much like a curry. Classic Thai ingredients such as lemon grass, ginger, fish sauce, coconut, and basil create a light and lively soup. Shrimp or chicken could be added for a more substantial meal. Cut all the vegetables in advance, so the actual assembly and cooking time is short.
Heat the oil in a large, heavy pot over medium-high heat. Sauté the pepper and onion until the vegetables begin to soften and color, about 5 minutes. Add the garlic, ginger, and green curry paste, and cook for 1 minute, stirring constantly.
Add the coconut milk, stock, fish sauce, and sugar to the pot, and bring to a simmer.
Add the potatoes and carrots, and reduce the heat to low. Cover and simmer until the vegetables just begin to soften, 5 to 8 minutes.
Add the cauliflower and continue to simmer, covered, for 5 minutes.
Add the zucchini and green beans and cook, uncovered, until all the vegetables are crisp-tender, 5 to 10 minutes. If the soup is too thick, add more stock or water to thin slightly.
Stir in the basil and lime juice and serve hot.