Clean 3–4 lbs sterlet, remove the sturgeon marrow, salt the fish, and set it aside for awhile. Wipe the fish dry, coat with poppy seed, nut, or mustard oil, sprinkle with rusk crumbs, place in heated oil, and fry on both sides. Meanwhile, prepare the following sauce: Boil 1 glass each prunes and raisins. Fry 1 spoon each flour and poppy seed or olive oil almost until golden and dilute with 2 glasses boiling water or fish bouillon. Add the prunes and raisins, the juice from half a lemon, 1–2 bay leaves, 1–2 cloves, and 2–3 pieces sugar, or honey, or treacle. Boil for at least 15 minutes and pour over the fish on a platter. A little caramelized sugar may be added to the sauce.