In a large saucepan, saute onion in oil until tender. Add garlic; cook 1 minute. Stir in the chili powder and cayenne; cook 1 minute longer.
Stir in the ketchup, molasses, vinegar, Worcestershire sauce, mustard and pepper sauce. Bring to a boil. Reduce heat; simmer, uncovered, for 30-40 minutes or until sauce reaches desired consistency. Cool for 15 minutes.
Strain sauce through a fine mesh strainer over a large bowl, discarding onion.
Store in an airtight container in the refrigerator for up to 1 month. Use as a basting sauce for grilled meats or a serving sauce.
Recipe by Mandy's Recipe Box at https://mandysrecipeboxblog.com/spicy-sweet-bbq-sauce/