Puffed Apple Pancake

This turned out so well, the boys have requested it again this week!

1 cup milk
4 eggs
3 tbsp sugar
1 tsp vanilla
1/2 tsp salt
1/2 tsp cinnamon
2/3 cup flour
2 tbsp butter
2 peeled, cored, and thinly sliced apples
3 tbsp brown sugar
powdered sugar

Preheat oven to 425°F. Whisk milk, eggs, sugar, vanilla, salt, and cinnamon in large bowl until well blended. Add flour and whisk until batter is smooth. Place butter in 9-inch round baking stone/pan. Place dish in oven until butter melts, about 5 minutes. Remove dish from oven. Place apple slices in overlapping rows atop melted butter in baking dish. Return to oven and bake until apples begin to soften slightly and butter is bubbling and beginning to brown around edges of dish, about 10 minutes.
Pour batter over apples in dish and sprinkle with brown sugar. Bake pancake until puffed and brown, about 20 minutes. Sprinkle with powdered sugar, if desired. Serve warm.