Smear butter or oil to coat the entire surface of the 12-inch cast iron pan. Place the skillet in the oven on the center rack. Preheat the oven to 425°F.

Add the eggs, flour, milk, vanilla extract and salt to a bender and blend until smooth, scraping sides. Alternatively you can add the ingredients to a large bowl and whisk until smooth, 4-5 minutes.

Carefully open oven, pull out the oven rack, and pour mixture into the skillet from the oven. Bake until golden brown and puffy, about 20-25 minutes. Do not open oven during this time, or you could deflate the pancake.

Cut the pancake into 6 wedges and serve with desired toppings.