Begin by separating the egg whites and yolks into two different bowls; ensure that no yolks break. In the bowl with the yolks, whisk together milk, vanilla extract, and optional lemon zest. Sift in the flour and baking powder, mixing until smooth.

In the bowl with the egg whites, add white vinegar. Beat the egg whites on medium speed until frothy, about 1-2 minutes. Gradually add the sugar, beating until stiff peaks form.

Gently fold one-third of the meringue into the yolk mixture to lighten the batter. Add the remaining meringue, folding gently until no streaks remain.

Preheat a nonstick skillet over low heat for about 5 minutes. Lightly grease the pan, then scoop out and create 2-3 tall stacks of batter. Cover the pan and cook for 7-8 minutes.

Gently flip the pancakes and cover the skillet again, cooking for an additional 5-6 minutes until done. Pancakes should be fluffy and slightly jiggly.

Stack your soufflé pancakes on a plate and serve warm, topped with whipped cream, berries, powdered sugar, or syrup.