Combine ingredients: In a large, non-aluminum saucepan, combine the orange slices, all the whole spices, the red wine, maple syrup, and orange liqueur.
Heat gently: Cook over medium heat, stirring occasionally to help the sweetener dissolve. Bring the mixture to a gentle simmer, but do not let it boil, as this will cook off the alcohol and can make the wine bitter.
Simmer and infuse: Reduce the heat to low, cover the pot, and let it simmer gently for at least 15 to 30 minutes to allow the flavors to meld.
Strain and serve: Remove the pot from the heat and strain the mulled wine through a fine-mesh sieve to remove all the spices and fruit solids.
Garnish: Ladle the warm mulled wine into heatproof mugs or glasses and garnish each with a fresh orange slice or a new cinnamon stick before serving.
