Preheat your oven to 425°F (220°C). Place a 10-inch cast iron skillet (or similar oven-safe pan) into the oven while it preheats. This is crucial for getting a good puff, as the pan needs to be very hot.

In a blender, combine the eggs, milk, all-purpose flour, granulated sugar, salt, and vanilla extract (if using). Blend on high speed for about 30-60 seconds, until the batter is completely smooth and bubbly. Alternatively, whisk vigorously in a large bowl until smooth.

Let the batter rest for 5-10 minutes while the oven finishes preheating. This allows the flour to fully hydrate and helps achieve a better puff.

Carefully remove the hot skillet from the oven using oven mitts. Add the 2 tablespoons of unsalted butter to the skillet. The butter should melt and sizzle immediately, coating the bottom and sides of the pan.

Pour the prepared batter directly into the hot, buttered skillet. Immediately return the skillet to the preheated oven.

Bake for 15-20 minutes, or until the Dutch Baby is dramatically puffed up around the edges, golden brown, and the center is set. Avoid opening the oven door during the first 10-12 minutes to prevent it from deflating.

Once baked, carefully remove the Dutch Baby from the oven. It will begin to deflate almost immediately, which is completely normal.

Serve hot, dusted generously with powdered sugar, a squeeze of fresh lemon juice, and your preferred toppings such as fresh berries and maple syrup. Slice into wedges and enjoy immediately!