Heat some oil and fry 150g diced bacon until golden. Add 3 onions, sliced in rings and fry this until the onion rings are soft and golden. Then add 1 finely chopped garlic clove and 1 teaspoon fresh thyme leaves. Just heat it a little. Meanwhile season 250 ml creme fraiche to taste. Put 6 puff pastry sheets on a baking sheet coverd with baking paper. Spread 1/2 the creme fraiche over the puff pastry sheets, leaving a border of 1 cm. Put the bacon onion mixture on top of it and spoon the other half of the creme fraiche on top of it. Put the baking sheet in the preheated oven 200C (fan) for about 20 minutes. Enjoy!