Drizzle the washed fillet with lemon juice. Chop the parsley, dice the onions. Mix both with oat flakes, mustard, egg and crème fraîche. Spice up.
Bring 500 ml of water and 0.5 teaspoons of salt to the boil. Remove from the stove, pour in milk. Stir in the puree flakes. Beat vigorously after 1 minute. Pour into a greased baking dish.
Season the fish and place on the puree. Spread the herb mixture on it. Bake in a preheated oven (fan oven 175 ° C) for 30 minutes until golden brown.
A colorful salad with buttermilk marinade tastes good with it.
Tip: If you don`t like ready-made mashed potatoes, you can of course take on homemade mashed potatoes.