Prep Your Egg Yolks: In the bowl with your egg yolks, whisk in the milk, vanilla extract, and lemon zest (if using) until everything is smooth and combined.
Combine Dry Ingredients: In a separate small bowl, whisk together the fluffed and leveled flour and the baking powder.
Add Dry to Wet: Add the dry ingredients to the egg yolk mixture. Whisk gently until just combined. Don't overmix! A few small lumps are okay. Set this aside.
Whip the Egg Whites: Now for the magic! In the clean bowl with your egg whites, add the white vinegar or lemon juice. Start whipping the egg whites with an electric mixer (or whisk vigorously by hand if you're feeling strong!).
Add Sugar Gradually: Once the egg whites start to look frothy (like soap bubbles), start adding the granulated sugar, about a tablespoon at a time, while you continue to whip.
Whip to Stiff Peaks: Keep whipping until the egg whites are glossy and form stiff peaks. This means when you lift the whisk, the peak stands up straight and doesn't curl over. This is crucial for the fluff!
Fold the Meringue (Gently!): This is the most important step for fluffiness! Take about one-third of the whipped egg whites (the meringue) and gently fold it into the egg yolk batter using a spatula. Use a cutting motion, going down the middle and scooping up from the bottom, turning the bowl as you go.
Continue Folding: Add the remaining meringue in two additions, folding gently each time until just combined. You want to incorporate the whites without deflating them. A few white streaks are fine!
Heat Your Pan: Lightly oil a non-stick pan or griddle and heat it over very low heat. Low and slow is key!
Cook the Pancakes: Spoon generous amounts of batter into the pan. You can make them as big or as small as you like, just leave space in between. I usually make about 2-3 at a time. Add a splash (about 1 tablespoon) of water into the empty spaces in the pan, away from the pancakes. Immediately cover the pan with a lid to create steam.
Cook and Flip: Cook for 4-6 minutes per side, or until the bottoms are golden brown and they've puffed up significantly. Carefully flip them using a wide spatula (or two spatulas!). Add another splash of water and cover again. Cook for another 4-6 minutes, or until cooked through. They should feel light and airy.
Serve Immediately: Soufflé pancakes are best enjoyed right away! Stack them high!
Make Optional Whipped Cream: While the pancakes cook, or just before serving, whip the cold heavy cream, sugar, and vanilla in a clean bowl until stiff peaks form.
Top and Enjoy! Dust with powdered sugar, pile on berries, dollop with whipped cream, and drizzle with maple syrup. Get ready for pure bliss!