Either way, here's my favorite recipe. This isn't strictly "vegetarian" since it includes the rind from parmesan cheese. It's something you pretty much have to include since that is where the depth of flavor is coming from
2 small leeks (or 1 large), white and light green parts, sliced thin
2 medium carrots, peeled and diced
2 small onions, diced
2 medium celery stalks, diced
1 baking potato, diced
1 med zucchini, diced
3 c fresh spinach leaves, cut into thin strips
28-oz can whole tomatoes packed in juice, drained and chopped
8 c water
1 parmesan cheese rind (approx 5 x 2 inches)
15-oz can cannellini beans, drained and rinsed
1/4 basil pesto (or 1 T minced fresh rosemary mixed with 1 teaspoon minced garlic and 1 T extra-virgin olive oil)
Throw everything into a large pan except the beans and pesto and bring to a boil. Reduce heat and simmer, uncovered and stirring occasionally, until the vegetables are tender but still hold their shape, about an hour or 90 minutes or so.
Add beans and cook until just heated through, about 10 minutes. Remove pot from heat. Remove and discard cheese rind. Stir in pesto (or rosemary-garlic mixture). Adjust seasonings, adding pepper and more salt if necessary.