Preheat oven (electric cooker: 200 °C/circulating air: 175 °C/gas: see manufacturer). Wash 8 large potatoes (approx. 250 g each; see below) thoroughly, brush them off if necessary and pat them dry. Coat a baking tray with oil. Spread the potatoes on top, sprinkle approx. 1 tbsp. coarse sea salt over them. Bake in a hot oven for about 1 1⁄2 hours. Take out baked potatoes and break them open. Fill directly with the desired filling or serve the filling with it.
Peel 2 red onions and cut into fine strips. Wash 1 apple (e.g. Elstar), quarter, core and slice finely. Sprinkle with 1 tbsp. lemon juice. Wash 1 bunch of dill, shake dry and cut the tips finely.
Stir 500 g sour cream and 75 ml mineral water until smooth. Stir in dill, onions, apple and 500 g crab meat. Season with salt and pepper. Pour into the broken baked potatoes. Spread 50 g caviar on top.