Dutch Baby with Lemon Sugar

INGREDIENTS

• Equipment: a 10-inch cast-iron skillet
• 1/2 stick unsalted butter, cut into pieces
• 1/4 teaspoon pure vanilla extract
• 2 teaspoon grated lemon
• 1/3 cup sugar
• 1/8 teaspoon salt
• Accompaniment: lemon wedges
• 1/8 teaspoon grated nutmeg
• 2/3 cup whole milk at room temperature
• 2/3 cup all-purpose flour
• 1/8 teaspoon cinnamon
• 3 large eggs at room temperature 30 minutes