Peel and chop the onion. Clean or peel and wash the vegetables and cut them into bite-sized pieces. Wash the thyme, put some aside for garnishing and remove the leaves from the rest.
Heat the oil in a pot. Brown the onion and tomatoes in it. Add prepared vegetables and thyme. Stir in 3/4 l water and broth, bring to the boil. Simmer covered for about 15 minutes.
Rinse and drain the beans. Add to the soup with the noodles and simmer for the last 5 minutes or according to package instructions. Season to taste with salt and pepper.