Apple Butter
["9 c. peeled apple slices (thick; approximately 18 average size apples)", "4 c. sugar", "1/4 c. white vinegar", "2 Tbsp. cinnamon"]
["Mix in crock-pot and cook on low for 16 hours, covered.", "Mash with potato masher and cool."]
["apple slices", "sugar", "white vinegar", "cinnamon"]