Peel and wash the potatoes and cut them into thin slices. Peel garlic and press it through a garlic press. Season 200 g cream with garlic, salt and pepper. Grease a gratin dish and put the potato slices in it.
Pour cream over it and cook in the preheated oven (electric cooker: 200 °C/ gas: level 3) for 50-60 minutes. Grate the cheese and sprinkle it over the gratin about 30 minutes before the end of the cooking time.
Wash the turkey escalopes, dab dry and wrap with sage leaves. Tie up with kitchen string. Heat oil in a pan and fry the turkey steaks in it from both sides for 6-8 minutes. Season with salt and pepper.
Wash the apple, quarter it and cut it into slices. Cut the bacon into strips and fry until crispy in a pot. Add apple slices and steam for 2-3 minutes. Take out about 8 apple slices and put aside.
Deglaze remaining apple-bacon mixture with stock and remaining cream and bring to the boil. Thicken with sauce thickener and season with salt and pepper. Arrange turkey steaks, apple slices and potato gratin together with the sauce on plates and serve garnished with apple slices and sage as desired.