Preheat the oven to 350°F (180°C)
Separate egg yolk and egg white into two mixing bowls. Make sure the bowl for the egg white is dry and clean without any oils on the surface. If you accidentally drop some yolk in the white, fish it out with egg shell.
Mix egg yolk with milk and honey, whisk until well combined before adding the sifted flour. Mix until smooth but don't over mix. Set it aside.
Add vinegar/lemon juice in egg white, beat with an electric mixer on medium speed until foaming. Add sugar in two batches while beating and continue until soft peaks form when you remove your mixer. When the mixture starts to form ribbons in the wake of your mixer, turn the speed to low and continue to beat until egg whites can form soft peaks, that way, the larger air bubbles can be eliminated.
Scoop about half a cup of the egg white into the yolk mixture and mix with a spatula until it's well combined before pouring this mixture into the bowl with the egg white mixture.
Mix with a spatula from bottom to top in the motion of writing "J" while turning the mixing bowl, so the mixture can be well combined. Don't stir in a circular motion or over mix, as it will cause the mixture to deflate,
Pour the mixture into the skillet, and smooth out the surface with a spatula.