Preheat the oven to 250 degrees F. Combine the apples, apple cider, brown sugar and 1/2 teaspoon salt in a large ovenproof pot or Dutch oven over medium heat. Bring to a simmer, partially cover and cook until the apples are soft, about 20 minutes.
Remove from the heat and stir in the lemon juice, cinnamon, vanilla and cloves. Puree the mixture in a blender in batches until smooth (or use an immersion blender).
Return the mixture to the pot and bake, uncovered, stirring every 30 minutes, until thickened and deep amber, 2 1/2 to 3 1/2 hours (the timing will depend on the kind of apples you use). Remove from the oven and let cool completely, then transfer to an airtight container and refrigerate up to 5 days.