Bake cake in a 9x13 pan per box directions.

Let cake cool 10 minutes, then poke holes with the handle of a wooden spoon.

Pour condensed milk evenly over cake so it sinks into holes.

Dollop strawberry puree and blueberry puree across the cake.

Drag a knife through the purees to make swirls; don’t overmix.

Spread whipped topping over the top.

Chill at least 2 hours. Add fresh berries before serving.