Preheat the oven to 350 degrees F. Grease an oval ovenproof dish about 13 inches long. In a mixing bowl, whisk the eggs and 1/2 cup of the sugar. Scrape the vanilla bean and add the pulp to the egg mixture. Stir in the brandy and flour. Whisk in the milk to form a smooth batter. In a mixing bowl, toss the cherries with the remaining sugar. Place the cherries in the ovenproof dish. Pour the batter over the cherries and place in the oven. Bake for 40 to 45 minutes or until the cake is sponge like. Remove from the oven and cool for 5 minutes before serving. Serve the clafoutis warm. Garnish with powdered sugar.