Peel and wash the potatoes, grate them into thin slices and pre-cook them in boiling salted water for 5 minutes, then drain and drain.
Rinse the fish, pat dry, drizzle with lemon juice and season with salt and pepper.
Grease a baking dish, cover the base with a layer of potato slices, place the fish on top, and distribute the remaining potato slices around the fish.
Whisk the crème fraîche with the eggs and mustard, add the capers, season with salt, pepper and a little lemon juice, pour over the fish and potatoes.
Bake the casserole in the preheated oven at 200 ° C for 25 - 35 minutes on the 2nd shelf.
Cut the bacon into strips and fry them until crispy (be careful not to skip this step, otherwise the gigantic bacon aroma will be missing!) Chop the parsley and sprinkle with the bacon over the finished casserole.