The simplest and easiest way to make apple butter is in a crockpot, by letting applesauce simmer down until it thickens, and then adding cinnamon to taste. You shouldn’t need to add any sugar.
You could use store-bought applesauce if the flavor is good, or make your own (see my roasted applesauce for a recipe).
First, fill your crock pot with twice as much applesauce as you want to turn into apple butter.
Then, over low heat, the crock pot will simmer the applesauce down in 4 -6 hours. Make sure to leave the top cracked or off completely so the water evaporates. It’s really a matter of personal taste, but I reduce it by about half: the flavor is more intense and doesn’t taste overcooked. The more full the crock pot to start, the longer it will take to simmer down — if full to the brim it may take 8 hours.
Every so often – 30 minutes or a hour — stir well. You’ll know it’s done when it darkens and heaps on a spoon, although this is a gradual process, and just remember that something hot that heaps on a spoon would probably heap even MORE if it was room temp or cold. Add cinnamon to taste. I don’t add any sugar, and I don’t suggest you add any until the end, and then, use sugar sparingly . . .
Pour through funnel into prepared half-pint or pint jars. Since this is rather thick and somewhat sticky, you may need to use a hot clean knife to release air pockets in the jar. Process jars in water bath for 10 minutes at sea level, and 15 minutes at 5000 feet. It was so scrumptious today on a toasted bagel with a hot cup of coffee after the dog took me for a walk!