Peel, wash, slice or slice the potatoes finely. Layer in flakes in a wide casserole dish. Season 150 g cream with salt and pepper and drizzle over the potatoes.
First cook in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: stage 2) for approx. 20 minutes. In the meantime, wash the salmon, dab dry, sprinkle with lemon juice and season with salt and pepper.
Clean the chanterelles, wash them carefully and drain them. Peel and finely chop the onions. Strip thyme leaves from the stems. Melt butter in a pan. Sauté the onion in it. Add the chanterelles and fry over a high heat for 3 minutes.
Season with salt and pepper. Dust with flour. Deglaze with 100 g cream and stock. Boil up briefly while stirring, stir in thyme. Put salmon on the potato gratin. Spread chanterelle cream on top.
Finish cooking in the oven at the same temperature for another 25 minutes. Serve garnished with fresh thyme.