Preheat the oven to 375 degrees F. Peel and chop the apples into bite sized chunks. Combine chopped apples and light brown sugar in a bowl.
Microwave this apple mixture at 30 second intervals in microwave until sugar has melted. In a separate bowl, whisk together Bisquick, milk and melted butter together.
Stir in the cinnamon. Pour the batter into an 8x8 (or 9x9) baking dish, top with your apple/sugar mixture.
Bake for approximately 50-55 minutes, or until golden brown on the edges and center is still tender but not wet. Remove and let cool slightly before serving. Serve with vanilla ice cream, if you want.