Preheat the oven to 400° F.
Place the butter in a large skillet and transfer to the oven.
While the butter melts, add the eggs, flour, milk, sugar, vanilla, and salt to the pitcher of a blender. Blend until smooth.
Carefully remove the skillet from the oven and swirl the butter around to coat.
Pour the batter into the skillet and return to the oven.
Bake until the pancake is puffed in the center and golden brown around the edges, approximately 20 minutes.
Transfer the pancake to a wire rack to cool slightly.