Wash all your apples thoroughly (no need to peel). Core and quarter apples.

If using a slow cooker, cook your apples on high for four hours, until they have all broken down. Ladle into a blender, or use an immersion blender to process the apple sauce into a uniform, smooth sauce. It will still be quite runny at this point. Return to slow cooker and cook for another hour (or even two, if you have more apples than just the 2.5lbs specified here), until the applesauce has reduced sufficiently. When tested, it shouldn't really drip, but instead slowly meander down from your wooden spoon. Add lemon juice and cinnamon to your butter, and stir well to combine.

If you're pressed for time, though, feel free to cook these on the stovetop in a large, heavy-bottomed pot. The process will be the same, except you will keep your burner at medium-low and your cooking times will be 1.5 hours for the first cook, and 30-60 minutes on the second (depending on how many apples you're cooking).

If canning, this amount will yield about 2 half-pints (I know, I know, it really cooks down). Please ensure you have sterilized jars and lids submerged into boiling water at the ready when your sauce finishes cooking; ladle sauce into jars, wipe the rim to prevent sticking, and cover with metal lids. Screw the rings on very lightly, using only two fingers, and return to hot water bath canning pot for 10-minutes of processing.