In a blender or food processor, purée onion with vinegar until smooth. Add catsup, apple juice, brown sugar, oil, mustard, celery seed, Worcestershire sauce, hot sauce, garlic, cayenne and turmeric and blend well. Transfer mixture to a medium non-reactive saucepan and bring to a boil. Reduce heat to medium and simmer, stirring frequently for 20 minutes until sauce is slightly thickened. Let cool.
The sauce can be prepared up to a week in advance and kept in a covered jar in the refrigerator.
Remove crab from shells. Wash and pat dry. Over hot coals, cook on an oiled grill set four to six inches from the coals. Brush crabmeat often with sauce, and turn once. Cook for four to six minutes on each side, until tender.Makes 4 Source: