In a large bowl, whisk together the egg yolks, milk, vanilla extract and 2 tablespoons of the sugar until completely combined and slightly pale. Sift the flour and salt directly into the yolk mixture. Whisk until completely smooth with no lumps. The batter should be thin and pourable.
In a completely clean, grease-free bowl, beat the egg whites with the pinch of salt using a whisk or electric beaters until they hold firm, glossy stiff peaks. This step is the foundation of the dish's lightness and cannot be rushed or skipped. The bowl must be clean and dry as any fat will prevent the whites from whipping properly.
Add approximately one third of the whipped egg whites to the yolk batter and stir through completely to loosen the mixture. Add the remaining whites in two additions, folding gently each time with a large spatula using a cut-and-fold motion rather than stirring. Stop the moment the white streaks disappear. The batter should be light, airy and considerably thicker than it was before the whites were added.