Place butter in a large round pan and put it in the oven as it heats.
Meanwhile, crack 6 eggs into a blender and beat until they double in size, about 2 minutes.
Add the milk, vanilla, cinnamon and brown sugar and pulse a few times.
Add the flour and mix for 1 minute.
Retrieve the HOT pan from the oven and pour the ENTIRE blender batter into it, carefully.
Quickly return the pan to the oven and cook for 22 minutes. (This is the perfect amount of time in my oven; yours may require a couple less or more.)
Notes
Updated: I used to pour the melted butter into the blender batter but on a tip from an awesome reader, I started doing it this way and it’s awesome. You don’t need butter to serve it with AND it never sticks. Enjoy!