Preheat your oven to 350°F and grease a 9×13-inch baking dish.

In a small bowl, whisk together flour, baking powder, and salt.

Beat egg whites on medium speed, adding sugar gradually until stiff peaks form.

Blend egg yolks with remaining sugar until pale, then mix in milk, butter, and vanilla.

Gradually add flour mixture to yolk mixture, mixing gently.

Fold whipped egg whites into batter carefully in two parts.

Pour batter into the baking dish and bake for 23-25 minutes until a toothpick comes out clean.

Once cooled slightly, poke holes in the cake with a fork.

In a large measuring cup, combine condensed milk, evaporated milk, heavy cream, and vanilla. Whisk until smooth.

Pour half of the milk mixture over the cake, then the remaining mixture.

Cover with plastic wrap and refrigerate for at least 4 hours or overnight.

Whip heavy cream, powdered sugar, and vanilla until stiff peaks form.

Spread whipped topping over the chilled cake before serving.

Slice into 15 squares and serve chilled.