For the Cake

1. Preheat oven to 350°F. Coat a 9×13 baking dish with nonstick spray. Set aside.
2. In the bowl of your stand mixer fitted with the paddle attachment combine 5 egg yolks and 3/4 cup granulated sugar on medium-high speed for 4 minutes, until pale yellow. Scrape the bottom of the bowl once or twice during mixing, to ensure mixture is evenly combined.
3. Turn the mixer down to medium-low and add in the milk, vanilla, baking powder and salt. Mix for 30 seconds, scraping the sides of the bowl as necessary.
4. Turn mixer to low and add in the flour, mixing until just combined.
5. In another bowl using the whisk attachment on your stand mixer or a hand mixer, beat the egg whites on high speed until soft peaks form.
6. Add in the remaining 1/4 cup of granulated sugar and continue beating until stiff (but not dry) peaks form.
7. Fold the egg whites into the prepared batter until combined.
8. Pour the cake batter into the prepared pan and bake for 25-30 minutes, or until the cake is set on top, and a toothpick inserted comes out clean. Place the pan on a wire rack to cool.

For the Topping

1. When the cake is mostly cooled, combine the sweetened condensed milk, evaporated milk and 1/4 cup heavy cream in a medium bowl.
2. Using a fork poke the top of the cooled cake, creating tiny little holes all over. Pour the milk mixture evenly all over on top of the cake, making sure you get the edges.
3. Allow the cake to cool completely, and cover with cling wrap. Place cake in the refrigerator for at least an hour, or overnight.
4. When you’re ready to serve the cake, mix the heavy cream and powdered sugar together in your stand mixer fitted with the whisk attachment until thickened. Spread on top of the cake and dust with ground cinnamon, if desired.