Preheat oven to 350F (175C) and spray a 9x13 glass baking dish with baking spray. Set aside.

Place egg whites in a large bowl or in the bowl of a stand mixer and beat until foamy. Gradually add 1 cup (200g) of sugar, increasing speed to high and beating until thick and glossy with stiff peaks.

In the same bowl, place softened butter and the remaining 1 cup (200g) of sugar, and beat until creamy. Add egg yolks one at a time, stirring after each addition, then mix in vanilla extract.

In a separate bowl, whisk together flour, baking powder, and salt. Alternately add milk and flour mixture to the egg yolk mixture, mixing until combined.

Gently fold the egg white mixture into the batter until fully combined.

Spread the batter into the prepared pan and bake for 35-40 minutes.

Let the cake cool for 30-60 minutes. Then mix together condensed milk, evaporated milk, heavy cream, and vanilla extract for the topping.

Poke holes all over the cooled cake and pour the milk mixture over it. Chill for several hours or overnight.

Prepare whipped cream by beating heavy cream with powdered sugar and vanilla until thickened. Spread over the cake and sprinkle with cinnamon if desired.

Slice and serve. Enjoy!