Peel the potatoes and let them cool, then cut them into slices. Grease a mold with the oil and pour half of the potatoes into it. Mix the bacon and onions and place on the potatoes. Place the remaining potatoes on top.
Mix the flour with a little sour cream until smooth, add the rest of the cream and the egg and whisk everything well. Season with salt and pour the mixture over the potatoes. Sprinkle with the Emmentaler. Finally, spread the butter in flakes on top.
A salad goes very well with it.
Baking time: In the preheated oven 30 minutes with convection 180 °