Preheat the oven to 425°F (220°C).

Butter and flour a 10" pie plate, then set aside.

In a mixing bowl, whisk together the flour, sugar, and kosher salt.

In another bowl, whisk the milk, vanilla extract, and eggs until well combined.

Slowly whisk the dry ingredients into the wet ingredients, mixing until a smooth batter forms.

Pour the batter into the prepared pie plate.

Bake until browned in places, puffed in the center, and set around the edges, about 1 hour and 45 minutes.

Transfer to a wire rack and let cool to room temperature.

Chill in the refrigerator for 30 minutes before slicing and serving.