Saute onion and garlic in butter in a medium saucepan until tender.
Stir in remaining ingredients except corn syrup; bring to a boil.
Reduce heat, and simmer sauce, uncovered, 20 minutes, stirring occasionally.
Stir in corn syrup, and simmer, uncovered, an additional 10 minutes.
Use sauce for basting, or serve with, beef or ribs.