Slow-cooker Apple Butter

This is so easy—in fact, I let it cook overnight. The hardest part is peeling and cutting all of the apples. (I used small, old-fashioned apples from my uncle’s trees.) Store the jars in the fridge for up to 6 weeks.
6 pounds apples (use a mixture of types)
2 cups sugar
4 tsp. ground cinnamon
1/4 tsp. ground cloves
1/2 tsp. allspice
1/2 tsp. ground ginger
1/4 tsp. salt
2 Tbsp. balsamic vinegar

1. Peel, core, and thinly slice apples. Combine sugar and next 5 ingredients; toss with apples. Pack the mixture into a slow-cooker, making sure it’s at least two-thirds full. Cover with lid, and cook on HIGH for 1 hour. Reduce heat to LOW, and cook for 8 to 12 hours or until the apples are completely soft. Remove the lid, increase the heat to HIGH, and cook 1 more hour or until most of the liquid has evaporated. Stir in balsamic vinegar. Use an immersion blender to puree apple mixture until smooth. Ladle into jars; cover with lids. Allow to cool completely. Store in the refrigerator for up to 6 weeks.