1. Clean fish, discarding heads, and inner parts. Put in cold water and refrigerate for 8 hours or overnight. Change water once.

2. Remove skin from fish, cut a slit along back to bone, and a second slit along the inside to the bone. With both hands, slowly separate the fish to 2 fillets, discarding bone. Try to remove as many bones as you can. Remove the membrane from the inner side. Cut the fillets to slices, about 1 cm wide. Wash in cold water.

3. Now, remove the membrane surrounding the milt, and crush it to paste, adding sour cream, sugar and some black pepper. Add slowly the vinegar, stirring.

4. In a glass jar, put alternate layers of herring, onions and pour in the sauce. Add bay leaf and allspice. Keep refrigerated for 3 days at least, and enjoy.

Difficulty : easy. Precision