Potatoes (5 pcs.) boil in a uniform until half-cooked. Cut into rings with a thickness of approximately 0.7 - 1 cm.
Halibut fillet without skin and bones, add salt and pepper to taste on both sides.
In a bowl, add sour cream (4 tablespoons), add mustard, add dried rosemary (1/2 teaspoon), add salt and ground white pepper, add 3 tablespoons of water. Stir the mixture.
Chop the carrots with rings/straws/curly plastics. At the bottom of the baking dish, add 3-4 tablespoons of vegetable oil, then put the potatoes, a layer of potatoes with a little salt, then put the chopped carrots.
Chop the shallots into rings. Put onion rings on a layer of carrots.
Fillet of halibut liberally lubricate with mustard-sour cream sauce. Add the halibut fillet to the baking dish. The structure is once again sprinkled with vegetable oil. Cover the form with a sheet of foil and send it to the oven preheated to t190c.
Bake for about 20-25 minutes. 5-10 minutes before cooking, remove the foil and brown the top layer of fish on the grill.