Bourbon or rumoptional for serving; use 2 tablespoons per drink
In a very large stockpot, place the apples. Quarter the oranges, then remove the peels from one orange (leave the peels on the second orange). Add to the pot with the cinnamon sticks, cloves, and any optional spices. Cover with the water—you'll need at least 1 1/2 inches of open space at the top of the pot for the cider to simmer; add less of the water if your pot isn't quite large enough to hold it all and maintain that space.
Bring the water to a rapid simmer over high heat. Reduce the heat to low, cover, and let simmer for 2 hours, until the apples and oranges are completely soft.
Remove the orange sections with the peels still on (leave the second, peeled orange in). With a potato masher, mash the fruit against the bottom of the pot to break it down and release more flavor (if you don't have a masher, use a wooden spoon and press the fruit on the side of the pot). Continue simmering, uncovered, for 1 hour more. Your kitchen will smell amazing.
Strain the cider through a fine mesh strainer or a cheesecloth. Press the solids into the sieve to squeeze out as much liquid as possible. (I find it easiest to place a strainer on top of a large bowl, then ladle the cider into the strainer and press the solids in batches). Discard the solids.
If desired, return the strained cider to the pot (remove any remaining solids from the pot first). Add the maple syrup or brown sugar and the vanilla, stirring to combine and heating the cider gently if desired. Taste and adjust the sweetness as desired, adding 1 tablespoon of sweetener at a time (the amount you need will vary based on personal taste and the tartness of the apples). Enjoy warm or chilled (with or without bourbon), garnished with apple slices and cinnamon sticks.
FOR SLOW COOKER APPLE CIDER: Add the apples, oranges, spices, and water as directed to a slow cooker. Cook on LOW for for 6 to 8 hours or on HIGH for 3 to 4 hours. Roughly an hour before the cider is done, remove the unpeeled oranges and mash the remaining fruit in the slow cooker. Strain the cider into a clean pitcher or bowl, then stir in the syrup and vanilla.
FOR INSTANT POT APPLE CIDER: Add the apples, oranges, spices, and water (make sure it's enough to cover the ingredients) to an Instant Pot and stir. Cover and cook on HIGH for 15 minutes, then let the pressure release naturally. Remove the unpeeled oranges, and mash the remaining fruit. Strain the cider into a clean pitcher or bowl. Stir in the syrup and vanilla.
TO STORE: Refrigerate cider in an airtight storage container (a glass carafe or jar works well) or covered pitcher for up to 1 week.
TO REHEAT: Very gently rewarm the cider in a pot on the stovetop over low heat or in the microwave.
TO FREEZE: Freeze leftovers in an airtight freezer-safe bottle or jar for up to 3 months. Place the frozen cider container in a bowl (to catch any runoff), then let it thaw overnight in the refrigerator before serving.