Heat a 9-inch skillet over medium heat on the stove top.
Add 2 Tbsp butter, apple slices, and brown sugar.
Cook until the apples are fork tender.
Preheat the oven to 450 degrees F and place the skillet on the middle rack of the hot oven.
Blend together eggs, milk, flour, sugar, salt, and vanilla.
Mix for about 1 minute until frothy.
When the oven comes to temperature, remove the hot pan.
Quickly pour the batter on top of the apples and return to the oven.
Bake for 15 minutes or until the pancake is golden brown and puffy.
Serve warm with butter, caramel sauce, and a sprinkle of icing sugar.