Begin by preheating your oven to 400°F (200°C). This initial step ensures that your Dutch baby rises perfectly, creating the fluffy texture we all adore.

While the oven heats up, slice your Gala apples into 1/4-inch thick slices. You want them thin enough to soften while baking but still retain some body. Set them aside for now.

Next, place your cast iron skillet on the middle rack of the oven and add the butter to the pan. Let it melt as the oven heats up. This will allow the butter to foam and eventually brown, infusing the dish with a rich flavor.

In a mixing bowl, combine the flour, baking powder, sugar, and salt. Whisk these dry ingredients together. In another bowl, crack your eggs and whisk them together with the milk and optional vanilla until well combined. Pour this mixture into the dry ingredients and whisk until smooth. You could also use a blender for this step, which gives it a light, airy consistency.

Once the butter is melted and bubbly, carefully remove the skillet from the oven (remember, it’s hot!). Layer the sliced apples evenly over the bottom of the pan, allowing them to soak up that delicious butter. Immediately pour the egg mixture over the apples, covering them completely.

In a small bowl, combine the sugar and cinnamon. Sprinkle this mixture evenly over the top of the batter. This will create a sweet crust that is irresistible.

Finally, place the skillet back in the oven and bake for 20-25 minutes. The Dutch baby should puff up beautifully and turn a golden brown color. Don’t be alarmed if it rises more than you expect; that’s part of the charm!