Preheat oven to 375 degrees. Prepare a 9x13 casserole dish with nonstick cooking spray. Pull four of the biscuits apart in half through the middle (that is why you need flaky style so they will pull apart).
Place the biscuits into the casserole dish and press into a sort of crust on the bottom. Brush the top of those halved biscuits with half of the heavy cream.
Sprinkle half of the brown sugar over the biscuits. Bake the crust for 10 to 12 minutes or until the biscuits are beginning to brown on the edges.
Meanwhile, stir together the frozen fruit, sugar, cornstarch, vanilla until evenly mixed. Spread the frozen fruit mixture over the biscuits.
Pull the remaining four of the biscuits in half through the middle. Arrange the biscuits over the top of the berries. Brush the biscuits with the remaining heavy cream and sprinkle with the remaining brown sugar.
Place the casserole into the oven and bake for 13-15 minutes or until the top biscuits are cooked through. Allow the casserole to rest for 15 minutes prior to serving to thicken up inside. Serve topped with vanilla ice cream or whipped topping