Sauté onion in butter in a large skillet until tender. Add catsup, vinegar, salt, pepper, sugar, paprika, chili powder, mustard, hot sauce, and Worcestershire sauce; stir until well blended. Cover and simmer 20 minutes, stirring frequently.
Slice frankfurters in half lengthwise; drop into boiling water. Remove from heat; cover and let stand 5 minutes. Drain.
Add frankfurters to barbecue sauce, stirring to coat well. Cover and simmer 5 minutes or until frankfurters are thoroughly heated. Serve immediately.