Place the apples in a slow cooker.
6 1/2 pounds apples - peeled, cored, and sliced
In a medium bowl, combine sugars, cinnamon, nutmeg cloves, and salt.
1 cup granulated sugar, 1 cup light brown sugar, lightly packed, 1 tablespoon ground cinnamon, 1/2 teaspoon freshly grated nutmeg, 1/4 teaspoon ground cloves, 1/4 teaspoon ground allspice, 1/4 teaspoon salt
Pour the mixture over the apples and mix well.
Cook in slow cooker on low for about 10 hours, stirring occasionally, until the mixture is dark brown and starting to thicken.
Use an immersion blender to puree the apple butter until smooth. Continue to cook uncovered on low for about 2 hours, to remove most of the moisture. (you want a dark brown, thick mixture)
Stir in vanilla.
1 tablespoon pure vanilla extract
Spoon the mixture into sterile containers, cover and refrigerate for up to two weeks or freeze.
Serve on slices of bread, muffins, pork chops or just eat it with a spoon.