Preheat the oven to 350F. Lightly spray a 9x13 baking pan with a cooking spray.
In a separate bowl, beat the egg yolks with sugar until creamy and pale, then add vanilla extract and milk and beat until combined.
Add the dry ingredients to the egg yolk mixture. Mix until smooth.
In another clean, dry bowl, whip the egg whites with ¼ cup of sugar until stiff peaks form. Gently fold the whipped egg whites into the cake batter.
Pour the batter into a prepared cake pan and bake for 28-30 minutes or until golden and a toothpick comes out clean.