In a large bowl, sift together flour, baking powder, and salt.
Using an electric mixer, beat the egg whites on high speed. Gradually add ½ cup of sugar and continue beating until stiff peaks form.
In a separate large bowl, beat the egg yolks with the remaining ½ cup of sugar. Whisk until yolks are pale yellow. Add the vanilla and stir to combine.
Fold the egg yolk mixture into the egg whites just until combined. Add flour mixture, alternating with the milk, while folding (do not overmix).
Cut two 8” circles out of parchment paper and place on the bottom of each pan. Grease the sides of the pan and pour batter equally into the two pans, using a spatula to smooth out the batter into an even layer.
Bake for 20 to 25 minutes, or until a toothpick inserted in the center of the cake comes out clean. Remove from oven and allow cake to cool completely.
Strawberry Mousse Filling:
Add strawberries and ¼ cup granulated sugar in a food processor; pulse until smooth.
Pour the strawberry mixture into a medium bowl. Stir in the powdered gelatin; let set for about 10 minutes.
In large bowl, beat heavy whipping cream with remaining sugar until stiff peaks form.
Melt the strawberry mixture in the microwave in 30 second intervals until no lumps remain.
Fold the strawberry mixture into the whipped cream until well combined, then refrigerate for 30 minutes.
Transfer the mousse into a pastry bag.
Combine the evaporated milk, sweetened condensed milk, and whole milk in a small bowl.
Once the cake has cooled, even out the cake by cutting the tops with a serrated knife.
Using a fork, poke through from the edges to the center of the first cake layer, then place it on a cake stand.
Using a spoon, slowly drizzle half of the milk mixture over the top of the cake. Be sure to cover the entire surface, including the edges.
Spread an even layer of the strawberry cream over the first layer of cake.
In a circular motion, create a two-inch border by piping additional strawberry cream around the edge of the cake in a circular motion. Fill the inside of the circle with the diced strawberries.
Add a layer of strawberry cream on top of the diced strawberries.
Flip the second cake layer, making sure the top part is facing down. Poke holes from the edges to the center using a fork.
Place the second layer on top of the strawberry cream. Spread any bulging cream from the edges using an angled spatula.
Slowly pour the remaining milk mixture over the top of the cake using a spoon.
Pipe the remaining strawberry cream on top of the cake, starting from the center, and making a swirl until the top is completely covered.
Finish by placing the sliced strawberries on top of the cake, creating a mountain.