Preheat the oven to 180°C. Unroll the puff pastry and line a baking pan with it. Poke a few holes in it with a fork.
Peel and finely chop the onions and the garlic. Rinse the leeks and cut into strips. Heat butter in the pan and fry the onions, garlic and leeks. Let cool.
Fry the bacon cubes until golden brown
Beat the eggs with the cream. Add the cheese and season with a pinch of nutmeg, pepper, salt, parsley and garlic powder.
Divide the bacon cubes and the vegetables over the puff pastry. Pour over the eggs and place the quiche in the preheated oven for 25 to 30 minutes until the bottom is nicely browned and the filling has set. Let cool and take out of the baking pan.