Puffy Apple Oven Pancake

Preheat an oven to 400F Grease a 9-inch glass pie dish with butter.
Prepare the apple.
Peel the apple, then cut it into quarters and core.
Using a small knife, cut the apple quarters into small chunks.
Make the apple filling.
In a small bowl, using a fork, stir together 2 tablespoons of the sugar and 1/4 teaspoon of the cinnamon.
Add the apple chunks and toss with the fork until the pieces are evenly coated with the cinnamon-sugar.
Pour the apple chunks into the prepared dish, spreading them out evenly with the fork.
Set aside.
Make the batter
In a blender, combine the remaining 2 tablespoons sugar, the remaining 1/4 teaspoon cinnamon, the eggs, milk, flour and vanilla.
Put the blender lid on securely and, holding the lid down tightly, blend on medium speed until all the ingredients are well mixed and frothy, about 1 minute.
Bake the apples.
Put the dish in the oven and bake the apple chunks for 5 minutes.
Using an oven mitt, carefully pull out the oven rack until the dish is visible.
Do not remove the dish.
Pour the batter evenly over the apples.
Slide the rack back into the oven and close the oven door.
Bake the pancake.
Bake the pancake until puffed and brown, about 25 minutes.
Using oven mitts, carefully remove the dish from the oven and set it on a wire cooling rack.
Dust the pancake with confectioners sugar using a fine-mesh sieve.
Cut into wedges and serve immediately.
Serves 8.