Peel, core, and cut the apples into large chunks. Finely chop the apples in a food processor or by hand. Place chopped apples in a 5-6 qt. slow cooker. Add 1 cup light brown sugar, salt, 1 tsp. lemon juice, 1.5 tsp. cinnamon, 1/2 tsp. ginger, 1/8 tsp. cloves, and a pinch of cayenne pepper. Stir well with a wooden spoon or spatula. Cover the slow cooker and cook on high setting for 4 hours, stirring after 2 hours.

After 4 hours, open the slow cooker and use an immersion blender to puree the apples. Feel free to leave them a little chunky, based on your preference. If you don't have an immersion blender, use a regular blender, but let the apple butter cool off first so you don't burn yourself when transferring the mixture to the blender.

After pureeing the apple butter, return it to the slow cooker. Add 1 tsp. of vanilla extract and stir. Taste the butter and see if the flavor is to your liking. The best way to taste the apple butter is by removing a small spoonful of apple butter and letting it cool for about 10 minutes before tasting it because the flavor will change once it cools. If the mixture is too tart, add up to 1/2 cup more light brown sugar and an additional 1/2 tsp. vanilla extract. If too sweet and bland, add a pinch more salt and up to 2 tsp. lemon juice to taste. If you want a stronger spice flavor, add up to 1 tsp. more cinnamon, up to 1 tsp. more ginger, and another pinch of cloves. And if you'd like a spicier flavor, add a few more dashes of cayenne pepper to taste.

Once you've adjusted the seasonings, cover the slow cooker and turn it to the "low" setting for another 1/2 hour to 1 hour. After the apple butter is finished cooking, spoon into jars and let cool. Apple butter will keep for about a week in the refrigerator.