1. Add the butter to a 12 inch cast iron skillet.
2. Preheat your oven to 425F. and put the cast iron skillet in the oven. This will heat your skillet and melt the butter.
3. In a stand mixer add the eggs and beat on a high speed for 2 minutes. (I used 6 speed on my KitchenAid Stand Mixer)
4. Continue mixing at a high speed and slowly add in the milk.
5. Add the flour 1 spoonful at a time.
6. Scrape down the sides of the mixing bowl as needed.
7. Add in vanilla.
8. Pull your cast iron skillet out of the oven and pour mixture in. The mixture may already start to cook at the bottom. Give the mixture a light stir to mix with the butter. Do not scrape the bottom of the skillet.
9. Place cast iron skillet back into the oven and cook for 20 minutes.
10. Let cool for a few minutes before sprinkling on powdered sugar with a mini mesh strainer.

For the Vanilla Sauce

1. Melt butter in a small sauce pan on low heat.
2. Combine sugar and cornstarch then add to butter.
3. Stir in milk and the light corn syrup.
4. Cook and stir over medium heat until mixture comes to a boil.
5. Boil for 1 minute then remove from heat.
6. Stir in vanilla.
7. Pour sauce over the Dutch Baby or on individual slices.