1In 3-quart saucepan, heat butter over medium heat. Add onion and garlic; cook 8 to 9 minutes, stirring occasionally, until tender.
2Stir in remaining ingredients. Heat to boiling. Reduce heat to low; simmer 30 minutes to blend flavors, stirring occasionally.
3Remove and discard lemon slices. Store covered in the refrigerator up to 2 weeks.