Preheat your oven to 375ºF. Remove the top rind from the brie wheel and place the cheese in a small oven-safe dish, such as a pie or gratin dish. Transfer the dish to the oven and bake until the brie begins to soften and melt, about 7 minutes.
Remove the dish from the oven. Generously spoon cranberry sauce over the brie and drizzle with honey, if desired. Mix slightly to blend the flavors. Position the rosemary sprig on top of the brie and return the dish to the oven.
Continue baking for an additional 10–15 minutes, or until the cheese is fully melted and bubbly. Serve the warm dip alongside crusty bread or crackers for dipping.