1. Bring first 3 ingredients to a boil in a medium saucepan over medium-high heat. Reduce heat to low, and simmer 5 minutes or until cranberries pop. Pour mixture through a wire-mesh strainer into a bowl, using the back of a spoon to squeeze out juice. Discard solids.
2. Transfer cranberry mixture to a large pitcher. Stir in wine, brandy, and orange juice. Chill 2 hours. Serve over ice; garnish with cranberries and fruit slices, if desired.
To serve as a warm mulled cocktail, transfer mixture to a Dutch oven and heat just until it begins to boil. Garnish, if desired.