Cook the tortellini in boiling salted water for 13-15 minutes. Peel or clean and wash the carrot and leek. Cut carrot into sticks, leek into rings
Sauté the carrot and leek in hot fat in a pot. Stir in 3/4 l water and stock. Bring to the boil, cover and simmer for about 5 minutes
Wash the basil and chop finely, except for a little to garnish. Wash, quarter, seed and dice the tomatoes. Leave both to stand briefly in the soup
Coarsely grate the parmesan. Drain the tortellini and add to the soup. Season to taste and serve with Parmesan and the rest of the basil