Heat the rapeseed oil in a large saucepan and fry the onions with turmeric and black pepper. Add the carrots and sweet potato, stir everything and add the water, amaranth, barley and mountain lentils, zucchini, bell pepper and paprika powder.
Cover everything and let it simmer for about 45 minutes over a low heat. Stir in between with the wooden spoon.
Add tomato paste, soup powder, marjoram and cumin and simmer for another 10 minutes.
If necessary, season with a little curry, some chilli flakes or a splash of soy sauce and add a little water if necessary.