Fetch 3 medium bowls
Separate the egg whites from the egg yolks, putting each kind into one of the first two medium bowls
5 large eggs
In the third medium bowl, put the flour, baking powder, and salt
6 oz flour, 1-½ tsp baking powder, ¼ tsp salt
Stir to combine
To the bowl with the egg yolks, add the 6oz sugar
6 oz granulated sugar (for egg yolks)
Mix the sugar and yolks on high speed until the mixture is pale yellow
Add the ⅓ cup of milk and the vanilla to the mixture
⅓ cup whole milk, 1 tsp vanilla extract (for cake)
Stir to combine
Pour the mixture into the third bowl (with the flour, baking powder, and salt mixture) and stir gently until combined, without over-mixing
In the second bowl, use an electric mixer on high to beat the egg whites
When the whites begin to stiffen into peaks, gradually mix in the 2oz of granulated sugar, as you're still mixing with the mixer
2 oz more granulated sugar (for egg whites)
Pour this mixture into the third bowl also, with the other mixture
Stir gently to combine, scraping the bottom and sides of the bowl
Pour the combined mixture into the ungreased 9x13 metal pan
Smooth it over with a rubber spatula