Preheat oven to 425 F.
Whisk together eggs, milk, and vanilla (or lemon zest, if using).
Whisk in the dry ingredients (flour, sugar, nutmeg salt), and continue beating until a smooth batter forms.
Cube butter and place in 10-inch oven-safe pan.
Place the skillet in the preheated oven and leave it in there until the butter is melted (5 minutes). Watch the butter carefully to be sure that it doesn't burn.
Once the butter is melted, swirl it around to cover the bottom and sides of the skillet.
Pour the batter into the heated skillet and return the pan to the oven.
Bake 20 minutes until the pancake is puffed and golden.
Lower the oven temperature to 300 F and bake an additional 5 minutes.
Remove pancake, enjoy your aha moment as it will deflate almost immediately. Cut into slices and serve with lots of toppings!