For the dough put flour, margarine in pieces, 1⁄2 teaspoon salt and 4 tablespoons soy drink in a bowl and knead first with the dough hooks of the mixer, then with your hands to a smooth dough.
Wrap dough in foil and chill for about 1 hour.
For the filling, clean and wash the spinach. Peel and finely chop the shallots and garlic. Clean and halve the mushrooms. Cut soft tomatoes into pieces.
Preheat oven (electric cooker: 180 °C/circulating air: 160 °C/gas: see manufacturer). Heat olive oil in a large pan. Sauté the mushrooms in it for approx. 6 minutes and take them out. Steam spinach, shallots and garlic in the pan for 2-3 minutes until the spinach collapses.
Mix in soft tomatoes and season to taste with salt, pepper and nutmeg. Puree the tofu, 125 ml soy drink and tahini with a hand blender. Stir in the starch. Season to taste with salt, pepper and approx. 1⁄2 TL turmeric.
Roll out the dough on a floured work surface until round (approx. 30 cm Ø). Pour into a greased tart mould with a lifting base (28 cm Ø) and pull up the rim. Spread the mushroom and spinach filling on top.
Pour tofu mixture over it. Wash and halve the tomatoes and spread them on the quiche. Bake in the preheated oven on the lowest rack for about 1 hour.