Baked mackerel in a sleeve

Wash the mackerel, cut off the fins, and remove the gills. It has no scales, so no cleaning is needed. Slit the belly from head to tail (without touching the gallbladder), remove the entrails and black membrane. Optionally, remove the backbone and small bones (however, without the backbone, the fish may break and won't look as nice on the table). Make three shallow diagonal cuts on each side of the fish's outer surface.

Rinse thoroughly. Dry the fish with paper towels.

Salt and pepper the fish on all sides. Season with fish spices on all sides. Place the carcass with the inner side facing out. Optionally season with vegetable oil and lemon juice. On one half, place onion rings (can be left whole), on the other half - lemon slices. You can season again with spices.

Place the fish back in its original position. Insert lemon half-rings into the skin cuts.

Place the mackerel in a baking bag with its head at the bottom. Wrap the bag tightly around the fish's body and tie it. Bake in a preheated oven at 180 degrees for 35 minutes, then cut the bag and leave it in the oven for another 5-10 minutes.