Preheat grill to 450°. You can also use an oven set to a high temperature.
Place 10-inch dutch oven or cast iron skillet in grill to heat up.
In a blender or food processor,combine eggs, egg yolk, flour, milk, sugar, cinnamon, and vanilla.
Blend for 2 minutes until well mixed and smooth.
When grill has been running on high for about 10-15 minutes, open the barrel, and place the 4 tablespoons of unsalted butter in the hot pan. Close the lid and allow butter to fully melt and just begin to brown.
Using a hot mitt, swirl the butter briefly in the pan, and pour in pancake batter from blender.
Close grill lid and allow it to return to 450°.
Bake pancake for 20 minutes at high heat, checking once.
The pancake should start creeping up the edges of the pan, but remain shiny in the middle.
After 20 minutes, lower grill temperature to 300° and cook for 5 more minutes.
Remove from heat. Cut pancake into wedges and serve immediately with the toppings of your choice.