Spread the puff pastry on a pan. Bake it for 20 minutes on the top rack of your oven at 200℃ with parchment paper and baking stones (please refer to Step 6). Make sure to do this baking! It really makes a difference in taste.
Grate the cheese. Mince the carrot, thinly slice the mushrooms, and chop the bacon into 3 cm wide strips. Briefly parboil the spinach and chop into 4 cm long pieces.
Saute the garlic, bacon, mushroom, and spinach with butter. Season with soup stock granules and a pinch of salt and pepper.
Combine the eggs, heavy cream, milk, and 3 tablespoons of cheese. Add a decent amount of black pepper.
Fill the puff pastry with the filling, and pour the mixture from Step 4 over them. Top with the remaining cheese and bake for 30 minutes at 180℃ on the top rack of your oven.
About baking the puff pastry: If possible, fill to the edge of the puff pastry with the baking stones. It doesn't matter if you don't have quite enough, but take care not to ignore the sides!
Story Behind this Recipe
I wanted to serve something like this for brunch. I made mine easily with frozen puff pastry.
It's easier if you bake the puff pastry on the day before making the quiche. I recommend using a chunk of cheese; preferably parmigiano reggiano or comte! It really makes it different from when you use store-bought grated cheese or easy melting cheese.