Position oven rack one position up from the bottom and preheat oven to 400°F.
Peel and slice the peaches add to a medium bowl.
In a small cup or bowl, blend 2 tablespoons of sugar with 1/2 teaspoon cinnamon. Sprinkle over the peaches and gently toss to coat.
Place the butter into a large cast iron skillet and place in the oven to melt the butter. Remove from oven and swirl the butter to coat the pan.
Evenly spread the peaches over the bottom of the skillet and return to oven. Bake 10 minutes.
Meanwhile, add the eggs, milk, flour, vanilla, and remaining sugar and cinnamon in a blender. Blend on medium speed until blended, about 1 minute.
Once the peaches are done baking, remove from oven and pour the batter over the peaches. Place back in the oven and bake for another 20 minutes, or until the pancake is golden brown and puffy.
Allow to cool for a few minutes on a wire rack before dusting with powdered sugar. Yes, it will deflate and that is okay.