Cook the vegetables until done over low heat in some olive oil.Add the tomato paste, bake and extinguish with white wine, a Chardonnay. Then add the tomatoes and cook for 10 minutes in the pan without the lid.
Put the sauerkraut juice and baking powder in the sauce and stir well. Put the pan in the oven at 80ºC and let it stand overnight. The sauce turns black at the top and you stir it.
Pass the sauce through a passe vite and let cool. You can freeze the sauce.