Sweet Dutch Baby Pancake

1 medium apple
3 Tbles sugar
3/4 tsp cinnamon
2 Tbls butter
3 large eggs at room temp
1/2 cup milk at room temp.
1/2 cup flour
1/8 tsp salt
1/2 tsp vanilla
sugar for dusting

Heat oven to 425 degrees. Peel and quarter the apple, cut into thin slices. In a small bowl, mix 2 Tbls of sugar with 1/4 tsp cinnamon. Add the apple slices and toss until well coated. Place the butter into 2 equal pieces and place in a 9 or 10 inch glass pie pan and put into the oven until butter melts. Remove from oven and swirl butter around so that the whole pan is covered. Spread the apples over the bottom of the pan. Bake for about 10 minutes, or until the apples have softened slightly and the butter is bubbling and browning a little on the edges. Meanwhile, in a blender make the pancake batter by combining the egg, milk, flour, salt, and vanilla also add the remaining sugar and cinnamon. Blend on medium speed until well mixed, about 1 minute. Remove pan from oven and pour the batter over the apples, then bake the pancake until puffy and golden..about 25-30 minutes. Let cool (it will deflate). Dust the pancake with sugar and cut into wedges.