Preheat the oven to 325 degrees.
Separate eggs, whites go in a large mixing bowl and the yolks in a small ramekin and set aside.
In a saucepan, heat the whole milk. When warm, remove from heat and whisk in the cocoa powder. Let it set and cool to room temperature.
In a measuring cup, combine flour and baking powder, set aside.
Add salt to the egg whites and beat with a stand or electric mixer on medium speed until frothy. Increase the speed to medium-high until soft peaks form. Slowly add the sugar; beat until stiff peaks form.
Add yolks to beaten egg whites mixture and continue beating until combined.
Add flour mixture and cocoa milk alternately in batches to egg mixture. Add vanilla and continue beating until combined.
Pour batter into a lightly greased 13x9" baking pan spreading evenly. Bake for 30 to 35 minutes until a toothpick in the center comes out clean. Place the pan with cake on a wire rack and let cool completely, about an hour.
When cool, use a wooden skewer or long fork to poke holes all over the cake top.
In a bowl, mix the evaporated milk and condensed milk together. Pour over the cake evenly.
Refrigerate for 3 to 24 hours (best overnight). Cut cake and serve with whipped cream and other toppings of choice.
