1poundground lambrolled into 1-inch balls, or one 14-ounce can of black beans
1cupfrozen corn kernelsdefrosted
3smallzucchinisliced in half lengthwise and cut into 1/2 inch rounds
Melt butter in a large dutch oven over medium heat.
Add the leek, bell pepper, carrot, turnip (or parsnip) and cumin seeds. Cook until the leeks are soft, about 6 minutes, stirring occasionally. Add the turmeric, curry powder, and mustard seeds, cooking for 1 minute more. Add garlic and cook for another 1 minute.
Add the potatoes, stock, water, cauliflower, and salt. Increase the heat to high to bring to a boil, then reduce heat to medium. Let simmer uncovered for 20 minutes.
While the soup is simmering, heat a heavy skillet over medium heat. Brown meatballs on all sides (as well as you can with a ball), about 10 minutes total. Remove from heat. If using black beans instead of lamb, cook the beans in the skillet until hot.
Add the corn and zucchinis to the soup, cooking until the vegetables are cooked through, about 10 minutes. Remove from heat.
Remove 1/3 of the soup from the pot and set aside. Use a stick blender to purée the remainig 2/3 of the soup in the pot—be careful, this can make a huge mess!
Pour the unblended soup back into the pot and mix well. Add meatballs or beans and cook for another 5 to 10 minutes to incorporate flavors.