In a large pot, add the necessary amount of water for the soup (depending on the number of servings). Add the cabbage, diced turnips and leeks, and season to taste.
About 30 minutes before the end of cooking, add the pasta and the peeled, diced potatoes. In a separate pan, sauté the onion until golden, then add the peeled and crushed tomatoes. Add this mixture to the soup and let it finish cooking over low heat.
