If using a homemade angel food cake, ensure the cake has cooled completely before assembly to prevent tearing during slicing.

In a large mixing bowl, add the diced strawberries and gently mash them with the back of a fork to release some juice while maintaining texture. Fold in the thawed Cool Whip and mini marshmallows until evenly combined. Cover the bowl and refrigerate the mixture for 20 minutes to allow it to slightly firm.

While the cream mixture is chilling, place the angel food cake on a serving platter. Using a sharp serrated knife, carefully slice the cake horizontally into three even layers. Set the top two layers aside.

Spread an even layer of the chilled strawberry mixture over the bottom cake layer. Gently place the middle layer on top and repeat with another layer of filling. Add the final cake layer.

Use the remaining strawberry mixture to frost the top and sides of the cake until fully covered. Smooth lightly, maintaining a soft, rustic finish.

Refrigerate the assembled cake for a minimum of 90 minutes before serving to allow the layers to set and ensure clean slicing.