Fish with Vegetables Baked in Foil
Rinse fish fillets and pat dry, sprinkle with lemon juice and season with salt and pepper.
Rinse leeks and cut into fine strips. Peel celery and carrots and cut into sticks. Clean mushrooms and cut into slices.
Place large piece of strong aluminum foil on the countertop.
Arrange fish fillets on foil and spread with vegetables, cover with butter pieces and seal well.
Bake in preheated oven at 200°C (approximately 400°F) for about 25-30 minutes.
Carefully unfold foil and pour all resulting cooking juices into the pot. Add cream and bring to a boil, simmer briefly and season with mustard, salt and pepper.
Arrange fish with sauce and vegetables on plates. If desired, serve with boiled potatoes.