Add ice to a large punch bowl. If using chunks (as opposed to a large block of ice), fill the bowl just under half way. Add Cointreau and brandy. Using a ladle or long spoon, stir briefly. Add orange slices and cranberries (if using) and then pour in the champagne. Stir 12 times and let sit for a minute, so the ingredients can get acquainted.
This orange-flavored Christmas Punch is featured in Good Spirits: Recipes, Revelations, Refreshments and Romance, Shaken and Served with a Twist (Harvard Common Press, 2007) by A.J. Rathbun, senior editor for Amazon.com's kitchen department. "It's an old family favorite," he says.