Defrost the prawns. Peel, wash and roughly grate the potatoes. Mix with egg, flour, salt, pepper and nutmeg
Heat 2 tablespoons of oil in a coated pan (approx. 24 cm Ø). Add the potato mixture and press flat. Cover and fry over a low heat for 15-20 minutes. Halfway through the frying time, turn the Rösti over using a plate
In the meantime, rinse the prawns and pat them dry. Clean and wash the mushrooms and, depending on their size, halve or quarter them. Peel and finely chop the onion. Fry the mushrooms in 1 tbsp. hot oil. Add onion and prawns and fry for about 2 minutes. Stir in crème fraîche. Season to taste with salt, pepper and lemon juice
Wash and finely chop the parsley. Serve the Rösti with creamed mushrooms and prawns. Sprinkle with parsley