Preheat oven to 425 degrees F. Place a 10 inch cast iron skillet in the oven to heat up.
Caramelized Apples: In a skillet, cook the sliced apples with cinnamon, brown sugar, maple syrup, and butter for about 10-15 minutes, until softened and caramelized. Set aside.
Combine eggs, flour, milk, and granulated sugar in a blender. Blend until well combined.
Remove hot cast iron skillet from oven. Melt the 4 tablespoons of butter in the hot skillet, swirling it around to coat and cover the pan.
Add the pancake mix from the blender to the prepared hot skillet, and return to the oven. Bake for about 20-25 minutes, until puffed up. DO NOT open the oven before time is up, it will deflate the pancake. Instead, use the oven light and peek through the window if you can. If not, just trust the bake time and try at 22 mins.
Serve immediately with the caramelized apples. Dust with confectioners sugar. Enjoy!