Wash tomatoes, dry them, cut in half, cut out the stems. To dice tomatoes. Peel the onions and garlic and cut into fine cubes.
Heat the oil in a saucepan, sauté the onions and garlic in it. Add the tomato pieces and sauté briefly while turning several times. Pour in the broth, season with salt and pepper. Let everything simmer for 15 minutes until the tomatoes have crumbled. Puree the soup and strain it through a sieve to remove the stones and peel.
Briefly heat the soup again and season with salt, pepper, balsamic vinegar and sugar. Serve the soup with 1 teaspoon of pesto each.