Finely dice the onions & heat 4 tbsp oil. Fry the onion cubes for 5 minutes.
Add 2 cloves of chopped garlic.
Add 2 tablespoons of tomato purée.
Add 40 g flour.
Sauté for 10 minutes, stirring regularly.
Add 800 ml water.
Bring 1½ - 2 tbsp Wacker vegetable stock to the boil. Then simmer over a low heat for 10 minutes.
Season with 1½ - 2 tbsp soya sauce and black pepper.
Place everything in a saucepan or blender to puree.
Puree the sauce with a hand blender or in a mixer until smooth.