Defrost the spinach. Pour just under 400 ml of cold water over the soy granules and allow to swell for 10 minutes. In the meantime, clean, peel and finely dice the carrots. Clean the leek, cut into fine cubes, wash thoroughly and drain. Peel garlic and chop finely. Wash the tomatoes. Cut 3 tomatoes into quarters, clean and remove seeds. Finely dice the flesh.
Sauté the carrots and half of the garlic in 2 tablespoons of oil. Add the soy granules and fry for 10-15 minutes until crumbly. Fold in diced tomatoes and leek. Deglaze with tomato-vegetable juice and simmer for about 5 minutes. Season with salt, pepper, paprika and herbs.
Peel and finely chop the onion. Sauté onion and remaining garlic in 1 tablespoon of oil. Add the spinach and turn for 1-2 minutes.
For the béchamel sauce, heat the fat in a saucepan. Sauté the flour in it. Stir in milk and vegetable stock. Bring to the boil, simmer for about 5 minutes. Season sauce with salt and pepper.
Put some béchamel sauce in an ovenproof dish. Place 3 lasagne plates on top. Spread 1/4 of the soy sauce on top and cover with 3 lasagne sheets. Spread 1/4 of the soy sauce on top, spread 1/3 of the béchamel sauce on the soy sauce and cover with 3 lasagne sheets. Spread the spinach evenly on the soy sauce and cover with 3 lasagne dishes. Spread 1/4 of the soy sauce on it, spread 1/3 of the béchamel sauce on it and cover with 3 lasagne sheets. Spread the rest of the soy sauce on top and spread the remaining béchamel sauce on top. Cut 2 tomatoes and mozzarella into slices. Spread on the lasagne and bake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 40-45 minutes until golden brown. Garnish with rosemary.