For the dough, cut butter into cubes and knead with flour, 1 pinch of salt and 1 egg first with the dough hooks of the hand mixer, then with your hands to a smooth dough. Form dough into a ball, wrap in cling film and chill for about 1 hour.
In the meantime, wash the tomatoes, drain them and cut them in half. Clean and wash spring onions and cut into fine rings. Sort the spinach, wash and drain. Grate cheese roughly. Finely dice bacon.
Peel and finely chop the garlic.
Line a springform pan (22 cm Ø) with baking paper. Wrap the dough out of the foil and roll it out on a floured work surface in a round shape (approx. 35 cm Ø), place it in the form, pressing the edges well.
Prick the pastry base several times with a fork. Place baking paper on the dough, spread pulses on top. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for approx. 12 minutes until completely dark.
Heat the oil in a pan. Fry the bacon in it over medium heat until golden brown. Add garlic and fry briefly. Put bacon and garlic in a large bowl and mix with spring onions, tomatoes, cheese and spinach.
Whisk 12 eggs with double cream and add. Season mixture with salt and pepper.
Remove the base from the oven, remove the baking paper and pulses. Pour the egg and vegetable mixture onto the base. Quiche and on the lower rail of the preheated oven (electric oven: 175 °C/ convection oven: 150 °C/ gas: see
manufacturer) prebake for approx. 1 hour
Then bake for another 45 minutes on the middle rack at the same temperature. Cover with aluminium foil about 15 minutes before the end of the baking time. Remove the quiche from the oven, let it cool lukewarm on a cake rack, remove from the tin and arrange on a plate.