Preheat oven to 400 degrees. Core apples and cut into wedges. In a medium-sized bowl, gently toss apple wedges with 1/2 cup cider, brown sugar, lemon juice and 1/2 teaspoon of salt. Arrange in a single layer on a large baking sheet and dot with butter. Roast for 30 minutes.
Remove the pan from the oven. Pour the remaining cider over the apples and gently mix. Transfer the apples and any remaining liquid into a medium-sized saucepan. Using the back of a wooden spoon, mash the apples. Transfer the mashed apples to a blender or food processor and blend for about 15-30 seconds (any longer and the apple butter will become too liquified). Transfer the apple butter back into the saucepan. Add the remaining salt and the cinnamon. Cook over low heat for about 5 minutes, being sure to stir regularly. Remove from heat and allow the apple butter to cool to room temperature. Transfer the apple butter into an airtight container. When kept refrigerated, the apple butter will keep well for about 1 week.