Slice apples into large pieces, removing any brusies as you go. Place apples in the bottom of a 4, 5 or 6 quart slow cooker.
Add brown sugar, cinnamon, salt, vanilla and optional pumpkin pie spice to the slow cooker. Stir until well mixed with the apples.
Cook the apples on low for 8-10 hours.
Puree the soft apples using an immersion hand blender or transfer the ingredients to a food processor. Blend until smooth.
Place apple mixture back in the slow cooker. Cook on high for one hour uncovered or until thick to your liking. This allows the apple butter to thicken further and for some of the water to cook off further.
Allow the apple butter to cool, then enjoy on toast, biscuits, pancakes, with pork and more! Store extra in airtight containers.
Notes
You can use between 5-6 pounds of apples for this recipe. It doesn't need to be exact. See the notes in the article about different types of apples to try. I used Honeycrisp apples in this version which also gives the apple butter a lighter color than some varieties.
If you prefer to lower the sugar you can, it's added for taste.
If you prefer to make a lower-sugar version you can leave out the brown sugar and then add maple syrup to taste at the end. I usually start with a tablespoon of maple syrup per pound of apples and then adjust to taste after that.
This recipe makes between 4-5 cups of apple butter. The nutrition information is approximate and is based on a 2 tablespoon serving.