1
In blender, place plums and lemonade concentrate. Cover and blend on medium speed until smooth; set aside. In 2-quart saucepan, melt butter over medium heat. Cook onion in butter about 2 minutes, stirring occasionally, until tender. Stir plum mixture and remaining sauce ingredients into onions. Heat to boiling; reduce heat. Simmer uncovered 15 minutes, stirring occasionally.