Directions:

Preheat oven to 350 degrees F and line the bottom of a 10x15x1-inch rimmed baking sheet with parchment paper, making sure it lays flat on the bottom. Do not grease the pan.

Prepare cake mix according to package directions. Pour into prepared pan and bake for about 20 minutes, until the top is golden and the edges start to crack.
*NOTE: It will rise up in the pan significantly, possibly even over the top a little bit; even so, it should not flow over. If you're concerned, slip an extra baking sheet or a piece of foil underneath the pan before baking, just in case.

Loosen the cake from the pan edges while it's still warm; it will be a little sticky, like angel food cake usually is, but it should come away from the pan easily.

On a clean kitchen towel sprinkled evenly with ¼ cup powdered sugar, flip out the warm cake, peeling off the parchment paper and immediately rolling up the cake starting at the short end, WITH the towel inside.

Let cool completely at room temperature for 1-2 hours or toss it in the fridge or freezer to make it go faster and be sure it's completely cool before adding the filling.

In a large bowl, beat the cream cheese with an electric mixer until smooth. Add ¾ cup powdered sugar, vanilla and cream and beat on low speed until well combined; increase speed to high and beat for 3-4 minutes until fluffy and stiff peaks form.

Unroll cooled cake and spread with half of the filling. Place half of the berries on top of filling. Carefully roll back up (this time without the towel!) and place on a serving platter.

Spread top and sides of cake with remaining filling and top with remaining berries.

Serve immediately; leftovers are best eaten within 24 hours.