1-Prep the apples: Prep the apples: peel, core and chop 6 pounds of apples (about 12 medium) into roughly even pieces so they cook the same, toss with 2 tablespoons lemon juice so they dont brown.
2-Add to the crockpot: Add to the crockpot: put the apples in a slow cooker with 1 cup granulated sugar, 1 cup packed light brown sugar, 1 cup apple cider or unsweetened apple juice, 2 teaspoons ground cinnamon, 1/4 teaspoon ground cloves, 1/4 teaspoon ground nutmeg and 1/2 teaspoon fine sea salt; stir to combine.
3-Slow cook until very soft: Slow cook until very soft: cover and cook on low for 8 to 10 hours or on high for 4 to 6 hours, until the apples are completely collapse-y and the juices are reduced and fragrant.
4-Puree the mixture: Puree the mixture: use an immersion blender right in the crockpot or transfer small batches to a blender and puree until silky smooth. Be careful hot stuff splatters.
5-Reduce to apple butter consistency: Reduce to apple butter consistency: uncover and continue cooking on low, stirring every 15 to 20 minutes, until it’s thick and spreadable – usually another 1 to 3 hours depending on how much liquid you started with. Dont rush it, but watch the bottom so it doesnt burn.
6-Make the salted caramel: Make the salted caramel: in a small heavy saucepan over medium heat melt 1/2 cup packed dark brown sugar with 4 tablespoons unsalted butter, stirring until bubbly; remove from heat and carefully whisk in 1/3 cup heavy cream until smooth and glossy. Let it cool a minute or two so it doesnt seize when added.
7-Finish the apple butter: Finish the apple butter: stir the warm caramel into the thickened apple butter along with 2 teaspoons vanilla extract. Taste and add 1/2 teaspoon flaky sea salt, then more to taste if you like it saltier.
8-Cool and store: Cool and store: let the apple butter cool a bit, then transfer to jars or airtight containers. Refrigerate for up to 2 weeks or freeze for longer storage. If you want to can it, follow an approved water bath canning recipe for fruit spreads.
9-Tips and hacks: Tips and hacks: if it’s too thin keep simmering uncovered, if it seems too sweet add a squeeze of lemon; always stir toward the end to prevent scorching, and try a spoonful warm on toast right away because you wont be able to wait.