Heat the oven to 425 degrees F. Combine the biscuit mix and the cheddar cheese then stir in the milk and butter. Spread the dough into two greased 8-inch layer pans and bake in the preheated oven for 20 minutes. Combine the brown sugar, cornstarch, cinnamon and salt in a large saucepan. Stir in the water and cook until clear and thickened. Att the apples, cover and simmer until the apples are tender. Spoon half of the apple mixture over one layer. Top with the second layer and remaining apples. Serve warm with whipped cream for a topping.