How to Make It
Preheat oven to 425°F. Place a 10-inch cast-iron skillet in oven. (Do not remove skillet while oven preheats.)
Whisk together flour, milk, eggs, salt, and 1 teaspoon of the pepper in a medium bowl until no lumps remain, about 1 minute.
Toss together cheese and remaining ¼ teaspoon pepper in a small bowl.
Remove hot skillet from oven, add butter, and swirl to melt. Immediately pour batter into hot skillet. Top with cheese and bake until golden and puffed, 15 to 18 minutes. Serve warm.