Preheat oven to 180 °. Cut meat into 3cm cubes. Peel potatoes und cut them into thin slices. Rip apart and cut sourcrout. Hackle onions and crush juniper berries. Coat a baking dish with butter and add sourcrout. Sprinkle with juniper berries and put meat upon sourcrout. Arrange onions upon meat and spice with salt, pepper and paprika powder. Crush garilc over all and add potato slices finally. Spice with salt and pepper. Mix milk with quark well and pour over dish. Close baking dish and cook in oven for about 2,5 hours.