Hungarian Crockpot Meatballs

Made these at a our party recently, and they were a hit.  I've used it with 2 lbs. of stew meat, cut into cubes, and cooked for 8-9 hours, then served over noodles.  For this version, I used 3 lbs. of ready made frozen meatballs from Costco (half a bag).  I had never used pre-made meatballs before, so I was a little nervous, but they were a hit with this sauce.
Either 2 lbs. of stew meat or 3 lbs. of frozen meatballs
1/2 cup ketchup
1 medium mild onion (Vidalia) chopped or sliced
1 clove garlic, minced
2 tbs. Worchestershire Sauce
1 tbs. brown sugar
2 tsp. salt
2 tsp. paprika
1/2 tsp. dry mustard
1 cup water
1/4 cup flour (for thickening sauce near serving time, if desired)

Place meat in crock pot, cover with onion.  Combine garlic, ketchup, Worchestershire Sauce, sugar, paprika, salt and mustard.  Stir in water, and pour over meat, and cover.  For stew meat, cook on low for 9 hours.  For meatballs, cook on high for 2-3 hours.  If sauce needs thickening, stir flour into a small amount of water, then stir into pot, then cook on high for 15 min. to thicken.  Makes 5-6 dinner sized servings with stew meat.  Source: Crockery Cookery by Mable Hoffman