Place skillet in the center rack of your oven, close the oven door, and preheat oven to 425F (220C).

In a blender, combine milk, flour, eggs, sugar, vanilla extract and salt (do not add the butter here). Blend for 10 seconds, pause and scrape the sides of the blender with a spatula if all ingredients aren’t incorporated, and blend another 5-10 seconds longer. Set aside while oven fully preheats.

Once oven reaches 425F (220C) (and make sure it truly reaches temperature, it’s ideal to have an oven thermometer in your oven or to let it run an extra 5 minutes or so after it tells you it’s preheated to ensure it’s hot enough), carefully use oven mitts to remove cast iron skillet from the oven. Immediately add butter to the skillet and swirl so it completely coats the bottom of the pan as it sizzles and melts (butter should begin to brown).

Immediately pour contents of blender evenly into skillet and, carefully, using oven mitts, return skillet to center rack of oven and bake for 20-23 minutes, until Dutch baby is puffed and golden brown all over.

Serve warm. I’ll usually use a knife or pizza cutter to cut into wedges. We like ours with a sprinkling of powdered sugar. The Dutch baby will shrink as it cools, this is normal!