Cook tripe with onion in milk for 2 hours. Let cool and mince once.
Combine tripe, beef, and pork in bowl. Add garlic and spices. Cover with a clean cloth and rest in the refrigerator overnight. Soak pig's casing in cold water, cover, and let stand overnight, refrigerated.
Place cold water in saucepan and season with salt. Cut apples and potatoes into 1/4-inch thick slices and add to pan. Cook, covered, for 30 minutes.
Meanwhile, drain pig's casings and run warm water through it by placing one end over faucet.
Attach casing to end of sausage funnel on a mixer and place seasoned sausage meat onto the scoop. Gently force the sausage mixture through the funnel into the casing. When 12 inches long, tie ends of casing together, forming a ring. Repeat two more times, making sausage links slightly shorter each time, so they will all fit nicely inside each other in frying pan.
Place in frying pan, the smaller rings inside the bigger ones. Cover with water and cook for 7 minutes. Drain and cool.
Add clarified butter to pan. Prick sausages and add to pan. Cook 5 minutes, turning once.
Drain potatoes and apples and mash together. Season with salt and pepper and mix in butter. Return to heat to dry out slightly.
To serve, scoop potatoes and apples onto platter. Place sausage rings on top.