Prep the fruit and spices: Rinse the orange and apple. Slice them into rounds.
If you like, poke some cloves directly into a few orange slices for easy removal later.
Load the crockpot: Pour the apple cider into the slow cooker. Add orange slices, apple slices (if using), cinnamon sticks, star anise, and ginger.
Sweeten lightly: Stir in brown sugar or maple syrup if your cider isn’t very sweet. Start small.
You can always add more later.
Slow cook: Cover and cook on Low for 3–4 hours or High for 1.5–2 hours, until fragrant and deeply spiced.
Finish and adjust: Turn to Warm. Remove the orange slices if the rind starts to taste bitter. Stir in vanilla extract, then taste and adjust sweetness or spices.
Serve: Ladle into mugs.
For adults, add 1–1.5 ounces of bourbon, rum, or apple brandy per serving. Garnish with a cinnamon stick or orange slice.
Hold for a party: Keep on the Warm setting for up to 4 hours. Top off with a bit more cider if the level gets low.