Lamb Rack in Yogurt Sauce

Sprinkle the meat with salt and black pepper. Drizzle with butter and roast until it browns, then remove. Sweat the onion in the butter left from the roasted meat with a little water. When the water boils, add the flour. Fry until it browns, then pour in the chilled yogurt beaten together with the fresh milk. Put the meat into the sauce and roast until tender. Slice the lamb and blend the sauce smooth. Serve with mashed potatoes or rice.