Combine egg yolks, flour, milk, 2 teaspoons white sugar, vanilla extract, and salt in a bowl; whisk until batter is smooth.

Combine egg whites and lemon juice in a glass, metal, or ceramic bowl and beat until soft peaks form. Add egg whites to yolk mixture and carefully fold in using a spatula until just combined, using as light a touch as possible.

Melt 1 tablespoon butter in a non-stick pan over medium heat. Transfer batter into the hot pan, cover, and cook until the bottom is golden brown and bubbles appear on the surface, about 4 minutes.

Use a spatula to cut the pancake into 4 sections and flip over. Cover and cook for another minute. Use 2 spatulas to tear or cut the pancake into 1 to 2 inch pieces.

Add remaining butter in little pieces to the pan and sprinkle with remaining 2 teaspoons white sugar. Cook tossing and stirring for a few minutes until pancake pieces are lightly caramelized at the edges.