Place the blueberries in a small nonstick skillet over medium heat. Swirl the pan periodically as the berries become darker in color and the juices begin to release, approximately 5-6 minutes. Remove from the heat and use a potato masher to mash the blueberries and make a compote. Stir in the confectioners’ sugar.

Heat a large skillet over medium or medium low heat (use medium low if you don’t want to rush building the grilled cheese). Butter both sides of the brioche and once the pan is hot, lay both slices down in the pan. Once they’re golden brown, flip them over. While the other sides brown, carefully layer the brie on top of one slice and place the chocolate on top of the brie. Spoon the blueberry compote on top of the chocolate. When the bottoms of the brioche are golden brown, place the plain slice on top to finish building the sandwich.

Dust with additional confectioners’ sugar and serve immediately.