Saute onion in oil in a large pot. After it has browned slightly, add the rest of the vegetables and water to cover. Add spices. Bring to a boil, then lower to a simmer for about an hour until the vegetables are tender.
Puree with immersion blender. If pareve--add a few tablespoons of white wine. If dairy-swirl some plain yogurt in each bowl after the soup is in the bowl.