Cut the potatoes into thin slices about 3mm thick and drizzle with olive oil and pepper.
Cut the puff pastry into 4 horizontal rectangular pieces 8cm wide, and coat in the onion jam. Place a bacon rasher on the top half the pastry strip, then a layer of overlapping potato and thin slices of the whole red onion. Then add slices of camembert under the bacon, potato and onion on the pastry.
Fold the bottom half of the pastry and the camembert up over the top half, then roll the whole strip up from one end to make a rolled rose. Place each of the rolled roses in the muffin tin.
Bake for 20 minutes at 180°C, then let the roses cool slightly before serving with courgette on the side.