Wash the soup greens and cut them coarsely. Wash parsley, pluck off leaves and put aside. Wash thyme. Wash and halve the tomatoes. Cut parmesan rind into smaller pieces. Remove loose skin from garlic bulb and onions.
Cut the onions in half and roast them in a pot without fat darkly with the cut surfaces facing down, so that the broth gets a nice colour.
Add water, vegetables, parsley stems, tomatoes, parmesan, garlic, black peppercorns, bay leaves and salt.
Slowly bring to the boil and simmer for about 1 hour. Pour stock through a fine sieve and season with salt and pepper.