For the puff pastry slices with bacon, finely chop the onion, cut bacon into very small cubes. Preheat oven to 200 degrees convection.
Mix all ingredients well. Roll out the puff pastry, spread the filling lengthwise so that the edge is free on both sides. Roll up puff pastry and place in freezer for about 1/2 hour.
Cut puff pastry into slices about 2 cm thick and place on a baking sheet lined with baking paper, spacing them slightly apart. Bake the puff pastry slices for about 20 minutes.