Rinse the apples and orange. Quarter the apples (no need to peel or core) and thickly slice the orange.
Combine the apples, orange, cinnamon sticks, cloves, allspice berries, and water in a large, heavy pot. Bring to a boil over high heat.
Reduce to a gentle simmer, partially cover, and cook 75β90 minutes until the apples are very soft and breaking apart and the liquid is intensely fragrant.
Uncover. Mash the fruit thoroughly with a potato masher, then simmer 20β30 minutes more to concentrate the flavor; the liquid should reduce slightly and taste robustly apple-forward.
Set a fine-mesh strainer lined with cheesecloth over a clean pot or large bowl. Ladle the hot mixture into the strainer and let drain, then press firmly on the solids to extract as much liquid as possible; discard the solids.
Return the strained cider to the pot over low heat. Stir in the brown sugar until dissolved, 2β3 minutes, tasting and adding a little more if desired.
Serve warm, or cool to room temperature and refrigerate up to 5 days or freeze up to 3 months. Stir before serving; natural sediments are normal.