Grease a quiche pan, dia 28 cm, with butter, line it with the puff pastry, pierce it several times with a fork and put the pan in the refrigerator until you are ready to use it.
Preheat the oven to 180 ° C top / bottom heat.
Heat some olive oil in a non-stick pan and first lightly roast the pine nuts and place them on a small plate.
Then sauté the onion cubes until translucent. Add the spinach, squeeze the garlic cloves and let thaw over low heat. Let as little water as possible. Season well with salt, pepper and nutmeg.
Cut the feta into small cubes and mix with the beaten eggs - you can add some cream - the grated cheese and the pine nuts. Then season a little if you like.
Put the spinach in the pan lined with puff pastry and pour the egg-feta-pine nut mixture over it and smooth it out well. Finally, press the halved cocktail tomatoes into the mixture.
Bake on the middle rack for about 45 minutes.
Tip: Turn on the fan at the end, this will turn the quiche nice and golden brown.