Preheat the oven to 350 degrees and prepare a 13 x 9 inch baking dish with cooking spray.
Melt margarine in a large heavy skillet over medium heat. Add sugar and stir until dissolved. Add cherries and stir to coat. Cook cherries, stirring occasionally, until juices are released and begin to reduce slightly, about 10 minutes. Remove pan from heat and stir in liquor of choice. Return pan to heat and simmer until juices thicken, about 5 minutes. Remove from heat and let cool slightly.
Make the brownie mix according to the directions.
Mix in the cherries jubilee. Pour the mixture into your prepared baking dish and bake for about 35 minutes.
Make the frosting by mixing the water and confectioner's sugar, drizzle over top before serving.