Peel the potatoes and pre-cook them in a saucepan of boiling water for about 10 minutes, but do not finish cooking. Then let cool in cold water.
Cut the peppers, garlic and onions into small cubes. Briefly sauté everything in a little olive oil in a pan.
Roll out the puff pastry and align with the long edge up or down. Spread the minced meat evenly on top, leaving 2 cm free at the top. Season the minced meat with thyme, salt and pepper. Spread the pepper mixture on the minced meat and sprinkle with the cheese. Brush the top edge with egg white and roll everything up from bottom to top.
Brush the finished roll with egg yolk.
Preheat the oven to 200 ° C fan-assisted air.
Cut the potatoes into slices. Also works great with an egg slicer. Lay the slices in a small baking dish. Season the cream with salt, pepper, nutmeg and marjoram and pour over the potatoes.
Place the minced meat roll and the bowl with the potatoes together in the oven on a baking sheet and bake on the middle shelf for about 30 minutes.