Preheat over to 425F.
In a blender, combine 1 cup of milk, 1 cup of flour, 3 large eggs, 1 teaspoon of vanilla extract, and a pinch of salt. Blend until smooth and well-mixed.
Place 2 tablespoons of butter in a cast-iron skillet and heat it in the oven until the butter melts.
Carefully remove the skillet from the oven, swirl the butter to coat the pan, and immediately pour in the batter.
Return the skillet to the oven and bake for 15–20 minutes, or until the Dutch baby is golden brown and puffed up dramatically.
Turn off the oven and let the Dutch baby bake for an additional 5 minutes to set.
Remove from the oven, dust with powdered sugar, and top with fresh berries or your favorite toppings.
Serve immediately and enjoy!