Core the apples and cut into eights. I leave the peels on, as I find that the pectin in the peels helps contribute to a thicker final product, you can peel if you'd like. Place the apples into the slow cooker and dd the water and apple cider vinegar.Cook on low for 6-8 hours or on high for 4 hours. You want the apples to get very tender.In a medium-sized, heavy bottom pan over medium-high heat, add the coconut milk, honey, sea salt and vanilla extract. Bring to an active simmer and then promptly reduce the heat to medium-low and allow to barely simmer untouched for about 55-60 minutes. The color should darken to a rich dark amber color and it should reduce by about half. Near the end, be sure to stir the caramel often, so it doesn't burn too much, a little sticking and browning is good, it enhances the rich caramel flavor. Once it has reduced and it's thick and luscious, remove from the pan and place in a glass bowl to cool down and thicken.Once the apples are very tender, use a slotted spoon to remove the apples (leaving the liquid behind and then pour it off) and place in a food processor or a high speed blender, process until the apples are pureed and mostly smooth. You may have to work in batches depending on the size of your blender or food processor. It is wise to leave the small lid off of the blender or the food processor to allow the hot steam to escape. You can also use an immersion blender.With the motor of the food processor or blender running, stream the caramel into the bowl with apples and purée until super silky and smooth. Add the cinnamon, nutmeg and lemon juice, continue to process until mixed in.Pour the apple butter back into the slow cooker (be sure you poured off the excess liquid that was left in there) and cook with the lid slightly ajar for another 1-2 hours, stirring occasionally, until you reach your desired darkness and thickness.Store in the refrigerator in airtight glass jars or containers. Will keep up to 2 weeks in the fridge. It freezes wonderfully, too.