Preheat oven to 350°.
Combine low-fat milk, hot coffee, and dark brown sugar in a medium saucepan over medium-high heat; bring to a simmer, stirring until brown sugar dissolves. Remove from heat, and cool to room temperature. Add egg substitute, vanilla extract, salt, and egg whites, stirring with a whisk. Combine egg mixture and bread in a large bowl, tossing gently to coat. Let stand 30 minutes.
Spoon half of bread mixture into an 8-inch square baking dish coated with cooking spray, and sprinkle evenly with chocolate chips. Top chocolate chips with remaining bread mixture. Bake at 350° for 45 minutes or until center is set. Let stand 10 minutes before serving.