Preheat Oven: Set to 425°F (220°C) and place a cast-iron skillet or baking dish inside to heat.
Make Batter: In a blender, mix eggs, milk, flour, sugar, vanilla, and salt until smooth. Let sit for 5 minutes.
Melt Butter: Carefully remove the hot skillet from the oven, add butter, and swirl to coat.
Bake: Pour batter into the skillet and bake for 18-20 minutes until puffed and golden brown.
Serve: Sprinkle with powdered sugar, add fruit or syrup, and enjoy warm!
