First, whisk flour, sugar, and salt together in a medium bowl. In a second bowl, whisk together the eggs, half-and-half, and vanilla or rum. Add the liquid ingredients to the dry and whisk until no lumps remain. Set aside to rest.

Preheat the oven to 500 degrees F., 425 degrees F. if using cast iron.

In a 10-inch skillet that can handle the oven heat, heat butter over medium heat. Add apples. Cook, stirring frequently, until the apples have begun to soften, several minutes. Add brown sugar and cinnamon and continue cooking until apples and sauce is just golden brown. Take the skillet off the heat and add the lemon juice.

Quickly pour the batter over the apples, pouring around the outside edges first and then filling in the center. Place the skillet into the oven. Reduce oven temperature to 425 degrees (or if using cast iron, keep at 425) and bake until the pancake’s edges are puffed and are nicely browned, about  15 – 18 minutes. Turn the pan halfway through cooking time.

Remove skillet from oven and loosen the pancake’s edges with a spatula. Invert onto a serving platter, sprinkle with powdered sugar, cut into wedges, and serve.