Preheat the oven to 350 degrees F. Place a metal stand mixer bowl in the refrigerator to chill (this will be used for the whipped cream topping).

Prepare two 8-inch cake pans by greasing them with nonstick cooking spray and lining the bottom with parchment paper. Wrap each cake pan with foil on the bottom and around the sides. Set these pans aside.

Mix the flour, sugar and baking powder in a small bowl. Set aside.

In a larger mixing bowl, combine the egg, milk, and vanilla and whisk to combine.

Add the dry ingredients to the egg mixture with the melted butter. Continue mixing until the batter is smooth and free of lumps.

Split the cake batter into the prepared pans (approximately 19 ounces per pan) and bake at 350 degrees F for 30 to 35 minutes or until the tester or toothpick inserted comes out clean.

Cool the cakes completely on a cooling rack for 30 minutes. Remove the cooked cakes from their pans and place them on a cooling rack while you make the filling and the whipped topping.

Whip the heavy cream in a medium-sized mixing bowl until stiff peaks form. Set this aside.

In another bowl, mix the mascarpone cheese, powdered sugar, lemon juice, and lemonade mix. Fold the whipped cream and the mascarpone mixture until combined. Set aside in the refrigerator while the whipped cream topping is made.

In the chilled metal mixing bowl, combine heavy cream, powdered sugar, vanilla unflavored gelatin, and the remaining package of Kool-Aid Lemonade. Using the whip attachment, whip at a low speed until the ingredients are combined, for about 1 minute, then increase the speed to high until there are stiff peaks of about 2 to 3 minutes.

Set the first cake bottom side up on a cake stand.

Add the lemon filling to the top, starting in the center and gently smoothing out towards the edge. Reserve some of the filling to fill in the sides once the top cake is added.

Add the second cake, bottom side down, on top of the lemon filling. Use the remaining lemon filling and a small spatula or the back of a spoon to fill in the sides or gaps, turning the cake stand and gently leveling the cake as much as possible.

Top it with the lemon whipped cream, starting with a thin layer on top and then adding a thin layer around the entire cake, repeating until the cake is covered. Any leftover whipped cream topping can be used when served.

Place the cake stand on a large baking sheet lined with parchment paper.

Sprinkle some of the crushed lemon snap cookies on top of the cake. To garnish the sides, add a spoonful of crushed cookies around the edge of the cake. Using the back/blunt side of a butter knife, bring the crushed cookies up onto the sides of the cake, gently pressing the crumbs into the sides. Continue turning the cake stand and adding crushed cookies to press up into the sides until the cake is covered.

Refrigerate for at least 2 hours before serving.