Preheat the Oven: Preheat your oven to 400°F (200°C) and place a heavy ovenproof skillet inside to heat up.
Prepare the Apples: Peel, core, and slice the apples into thin wedges. Once the oven is preheated, carefully remove the skillet from the oven and melt 2 tablespoons of butter in it over medium heat. Add the apples, sprinkle with 2 tablespoons of sugar and 1 teaspoon of cinnamon, and cook for about 5 minutes until the apples soften and become golden.
Make the Batter: In a mixing bowl, whisk together 1/2 cup of all-purpose flour, 1/2 cup of milk, and 2 large eggs until smooth. Optionally, add a pinch of salt.
Bake the Pancake: Pour the batter evenly over the caramelized apples in the skillet. Return the skillet to the oven and bake for 15-20 minutes, or until the pancake is puffed up and golden brown.
Serve: Remove from the oven and allow the pancake to cool slightly. Dust with powdered sugar (optional) and serve warm.