In a 500° F oven, braise the meat for 15 minutes.
Place meat in a deep pan and cover with water.
Add onion, dill, and pepper.
Simmer until meat is falling off the bone.
Cool overnight.
Remove fat.
Separate meat from bones.
Strain broth.
Add meat to broth reserving about a cup of liquid.
Bring broth to a boil
Mix flour, vinegar, sugar, salt, and additional dill into reserved liquid.
Stir reserved liquid into broth.
Serve over diced, boiled potatoes. It's best after having been cooled overnight and reheated.
