Chef John's Apple Butter
Any classic cooking apple should work in this recipe.
If you don't have a slow cooker you can certainly do it on top of the stove over low heat, as long as you use a nice thick-bottomed pot, and stir often. Another option would be to place the mixture in a large roasting pan, and cook it in a slow oven, stirring occasionally until dark and thick.
See my recipe for Irish Cheddar Spring Onion Biscuits.