Preheat oven to 450 degrees.place oven rack in the middle position. Put a10.to 12 inch cast iron skillet in oven while it is preheating. The pan should be empty. You want it to be warming up while you prepare your ingredients so its screaming hot.
In a blender add your eggs and beat on low until frothy, approximately 2 minutes. Add the milk and vanilla and beat for another minute.
Be sure your blenders lid is on tight.
Add the flour, cinnamon and sugar to the blender and put the lid on tight. Turn the blender on low and beat for another 3 to 5 minutes.
Note: I sift the flour through a mesh sieve to make sure there are no lumps.
Open your oven and using an oven mitt pull out the hot cast iron skillet and add the 8 tablespoons or half cup of butter. The butter should melt quickly as the skillet should be screaming hot. Tilt the skillet so that the butter coats bottom and sides.
Pour the prepared batter from the blender into the skillet. Slide the skillet back into the oven.
Set your timer for 20 to 25 minutes. Bake until the pancake puffs up.
Carefully remove the skillet from the oven and place on a towel on the counter or table.
I dust the top with powdered sugar and serve with maple syrup that I warmed on the stove with a little butter. You could also use warmed preserves, jam or pie filling. Eat and enjoy. Bon Appetite!