Roll out the puff pastry and place on a baking sheet, prick several times with a fork.
Preheat the oven to 200 ° C.
Steam the onion rings in the oil and butter mixture until translucent, you can do this in the microwave for 10 minutes. Mix with the bacon cubes. Spread this mixture on the puff pastry.
Whip the cream, eggs and spices vigorously and pour over the bacon and onion mixture.