For the pike-perch fillet, season the fish with salt and lemon juice and divide into appropriate pieces. Place in a buttered pan or dish, pour in some white wine or fish stock and cook in a preheated oven at 200 °C for about 6 minutes.
Meanwhile, bring the fish stock to the boil and purée or thicken in a blender with the cooked potato and pieces of ice-cold butter. Season to taste with salt, ground pepper, chives and minced garlic. Add cooked onion strips as a garnish.
Arrange the cooked pike-perch fillets in deep plates, pour the onion-garlic sauce over them and serve.
Preparation Tip:
Instead of garlic, wild garlic can be used for this pike-perch fillet recipe.