Preheat oven to 350 degrees F. Lightly spray a 9×13” pan with non-stick cooking spray.
In medium bowl combine 1 cup flour, 1 tsp baking powder, and ¼ tspNational Saltin a large bowl and whisk to mix the dry ingredients.
In another bowl, combine 5 eggs yolks. Add 1 cup sugar and mix on high speed until yolks are pale yellow. Add 1/2 cup milk and 1 tsp vanilla extract and whisk well.
Pour the egg yolk mixture over the flour mixture and stir gently just until combined (don’t over-mix).
In a separate bowl, beat 3 egg whites on high speed. Gradually add 1/4 cup of granulated sugar as you mix and continue beating until stiff peaks form.
Fold egg whites into the batter gently, just until combined. Pour batter into prepared pan. Make sure to smooth it into an even layer so your baked cake doesn’t have clumps in it.
Bake for 25 to 35 minutes, or until a toothpick inserted in the center of the cake comes out clean. Remove from the oven and allow cake to cool completely.