Wash approx 8 lbs of ripe peaches.
Halve peaches and remove pit. Don't worry about removing the peel. It will dissolve in the crock pot during the long cooking time.
Squish with a potato masher until you have a nice amount of liquid in the pot. You don't want these beauties to scorch! Cook on high for an hour or so. Then cook on low for 6-10 hours. Keep the lid cracked so steam can escape and the peach slurry can thicken. Time really depends on the juiciness of the peaches and the ambient humidity.
Blend with an immersion blender. (Yes, with the skins. They disappear. If you wanted, you could peel the peaches first, but that's too much work for me!)
Cook on high until it thickens, stirring occasionally. (If you put a scoop of the peach butter on a spoon, it should hold its shape and not release water.)
Add sugar to taste and other flavors as you desire. I usually pour in a few ounces of bourbon. It gives it a nice 'zing'.
Can 1/2 pints or 4 oz jars in waterbath for 20 minutes. Or freeze in suitable containers.
Use as a spread on toast, as a filling in crêpes, or swirled in plain yogurt.
(Note: this works with any stone fruit or apples, though I would peel the apples. Mix fruits for different flavor profiles.)