Once the oven is heated to temperature, place 2 tablespoons of salted butter in the cast iron skillet and cook in the oven for 10 minutes.
While the skillet is heating in the oven, using a stand mixer fitted with a whisk attachment, mix the eggs until pale and frothy, about 1 minute. Reduce the speed to low and slowly add in the milk, pumpkin pie spice, vanilla extract, and salt. Bump the speed up to medium and mix for 30 seconds. Then add in the brown sugar, all-purpose flour, and mix for about 1 minute (the batter will be very thin). Scrape down the sides if needed.
Carefully, remove the hot skillet from the oven. Pour in the batter in the skillet, sprinkle the raisins on top, and bake until puffed and golden-brown, 15-18 minutes.
Remove the Dutch Baby from the oven and top with chopped pecans, caramel sauce, and powdered sugar, serve immediately.
Notes
CAN YOU MAKE A DUTCH BABY WITHOUT A CAST IRON SKILLET?
Technically, yes you can make a dutch baby without a cast iron skillet. You can use a frying pan that is OVEN SAFE! That is the key. Some pans are only oven safe to a specific oven temperature. Always read manufacture instructions.