Make the cake: Preheat oven to 350° and grease a 9"-x-13" baking pan with cooking spray. In a large bowl whisk together flour, baking powder, and salt.
In another large bowl using a hand mixer, beat together egg yolks and 1 cup of sugar until stiff ribbons trail behind beaters, then beat in vanilla and set aside.
In a third large bowl using a hand mixer, beat egg whites until soft peaks form then gradually add in remaining 1/4 cup sugar and continue beating until stiff peaks form.
Add yolk mixture to dry ingredients and beat together. Add in milk and melted butter and beat until combined. Gently fold in egg whites until just combined. Pour batter into prepared pan and bake until a toothpick inserted into middle of cake comes out clean, 30 minutes. Let cool.
Meanwhile make filling: In a medium bowl whisk together sweetened condensed milk, evaporated milk, milk, and vanilla. Using a fork, poke holes all over cake, then pour milk mixture evenly over cake. Cover and place in refrigerator until all of the mixture is absorbed, at least 1 hour.
When ready to serve make whipped cream: In a large bowl using a hand mixer, beat together heavy cream and sugar until stiff peaks form. Frost cake with whipped cream and sprinkle with cinnamon-sugar. Serve with strawberries or other fresh fruit.