This is very easy, very inexpensive, and surprisingly delicious, from Mark Bittman’s How to Cook Everything Vegetarian. It’s good at any time of year because you can use canned tomatoes – and that’s all you should use unless you have really good fresh tomatoes available.
2 tb extra virgin olive oil
2 tb tomato paste (put the leftovers in waxed paper, like a tootsie roll, and freeze for later use)
1 large onion, sliced thinly and then cut in quarters
1 carrot, diced
salt and freshly ground black pepper
3 cups cored, seeded, peeled, and chopped tomatoes – canned are fine
1 tsp fresh or 1/2 tsp dried thyme leaves
2-3 cups vegetable stock or water
1 tsp sugar (optional)
minced fresh parsley or basil leaves for garnish (optional)
1. Put the oil in a large, deep saucepan over medium heat. When hot, add the tomato paste and let it cook for a minute, then add the onion and carrot. Sprinkle with salt and pepper and cook until the onion begins to soften, about 5 minutes.
2. Add the tomato and herbs and cook, stirring occasionally, until the tomato pieces break up, 10-15 minutes.
3. Add the stock, stir, and taste. Adjust the seasoning; if the soup is flat tasting, stir in the sugar. If it is too thick, add more stock or water. Garnish and serve.
Alternatives: if you want pureed tomato soup, replace 1 cup of stock with 1 more cup of tomatoes, and puree at the end with an immersion blender or food mill. If you want cream of tomato soup, replace the rest of the stock with milk, cream, or soy/almond/rice/etc milk.