Preheat the oven to 350°F.
Coat a 9x13-inch baking pan evenly with cooking spray.
Prepare the cornbread mix according to the package directions, using the required ingredients listed on the box.
Add the vanilla extract and orange zest to the prepared cornbread batter.
Stir gently until the vanilla and orange zest are evenly incorporated.
Spread half of the prepared cornbread batter evenly into the bottom of the greased baking pan.
Arrange the raspberries and blueberries evenly over the first layer of batter.
Spoon the remaining cornbread batter over the berries.
Spread the batter gently to cover the berries as evenly as possible.
In a small bowl, combine the brown sugar and cinnamon.
Sprinkle the brown sugar and cinnamon mixture evenly over the top of the batter.
Place the baking pan in the preheated oven.
Bake for 55 minutes to 1 hour and 5 minutes, or until the coffee cake is fully cooked and the center is set.
Insert a toothpick into the center of the cake to test for doneness. The toothpick should come out clean or with a few moist crumbs, but not wet batter.
If the top begins to brown before the center is fully cooked, cover the pan loosely with foil and continue baking until done.
Remove the pan from the oven and place it on a cooling rack.
Allow the coffee cake to cool for 15 to 20 minutes before slicing.
Slice into 8 portions.
Garnish each serving with whipped cream and additional berries, if desired.
Serve warm or at room temperature.