Preheat the oven to 425 degrees Fahrenheit.
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.