I start by zesting the orange into long strips (a vegetable peeler works great) and then squeezing out its juice. I combine the zest, juice, cloves, cinnamon sticks, allspice, and star anise.
I pour both bottles of red wine into the slow cooker, then add the citrus and spice mixture along with the dark brown sugar (reserving the brandy for later). I stir gently so the sugar dissolves.
I set the slow cooker to LOW and let it warm for about one hour — not boiling, but hot enough for flavors to meld. Once the hour is up, I switch to WARM, strain out the solids with a fine mesh strainer, and stir in the brandy. Then I’m ready to ladle and serve