Preheat the oven to 350°F. Grease the bottom of a 13x9 inch glass baking dish and set aside.

In a medium bowl, prepare the cake batter according to the instructions on the box. [If you prefer a homemade version, see note below]

Pour cake batter evenly into the prepared pan. Bake for 15-20 minutes until golden and puffy.

Remove from the oven and cool in the pan for at least 30 minutes. Meanwhile, make the strawberry mousse.

In a medium bowl, add 6 oz strawberry jello and 2 cups of boiling water. Stir slowly for one minute to dissolve.

Stir in 1 cup of cold water and set aside until half set (THICK BUT NOT FIRM). It takes about over 1 hour at room temperature or 5-10 minutes in the fridge. It's important to wait until it's half set, otherwise, your whipped cream and jello will separate when the mixture cools down.

Add the whipped cream/cool whip to the jello and mix until smooth. The mixture should be quite thick.

Once the cake is cool, spread the filling evenly across the cake using a spatula. Rap the pan on the counter a few times to level the filling and remove any trapped air.

Chill for at least 1 hour on a level surface in your fridge. Meanwhile, make the mirror glaze.

In a medium bowl, combine 3 oz jello powder with 1 cup boiling water and stir slowly for one minute until dissolved. Stir in ½ cup cold water and set aside to cool.

Remove the cake from the fridge. Arrange strawberry halves on top of the filling, approx. 4 widthwise by 5 lengthwise.

Once the jello is lukewarm, carefully pour it over the back of a spoon, dribbling across the top of the filling surface and over the strawberries.

Chill one more hour to allow the glaze to set. Congratulations, you're done - enjoy!