Preheat oven to 375 degrees F. Spray a 9 x 13 baking pan with cooking spray and set aside.

In a large bowl, mix together peaches, raspberries, sugar, cornstarch, and cinnamon until evenly coated. Pour fruit mixture into the prepared baking pan.

Bake for approximately 40 minutes, remove from oven and space raw biscuits evenly apart on the top of the fruit, sprinkle with cinnamon sugar and bake for another 10 minutes until golden brown.

Remove from oven and serve warm with ice cream if desired.