1. Heat the oven to 425°F and arrange the rack in the
middle. Place a large, seasoned cast iron skillet in the
oven as it preheats, at least 5 minutes.
2. Combine flour, salt, and orange zest in a large bowl and
whisk to break up lumps and incorporate; set aside.
Combine eggs, milk, and vanilla in a separate bowl and
whisk until eggs are broken up. Make a well in the center
of the flour mixture, dump in the egg mixture, and mix
until batter is thoroughly moistened and batter is slightly
lumpy, about 1 minute.
3. Using a dry kitchen towel or an oven mitt, remove the
skillet from the oven and add butter. Once butter melts, tilt
the skillet to coat the bottom and sides.
4. Pour batter into the skillet and bake in the oven until
puffed and golden brown on the sides, about 20 minutes.
Remove pancake from the oven and serve immediately
with pears or honey and a sprinkling of powdered sugar.