Mulling spices such as: star anise, cloves, cardamom pods, nutmeg
A stick or two of cinnamon
A full-bodied red wine
If you have cheese clothe, cut a large napkin sized square and place all the spices in. Tie the corners into a little bundle to pop into the wine mixture. Alternatively, the spices can go in loosely and you can strain the wine once it's ready.
Combine all ingredients in a pot over the stove or in a slow cooker and let steep for at least 30 minutes. The goal is to warm the wine just enough to extract all the flavours without becoming too hot and burning off the alcohol which happens at about 76° C so be careful not to boil.
Feel free to adjust the spice amounts to taste, add or swap your favourite spices to those listed above. I generally use a large pinch of each spice.
Add maple syrup or honey to taste if you'd like a little extra sweetness.