1. Peel, core and slice the apples.
2. Pre-heat oven to 425 degrees.
3. Melt butter in 10" cast-iron skillet. Once melted, add apples, cinnamon and sugar, cooking and stirring over medium-high heat until apples have released their juice and the juice has blended with the sugar, 3-5 minutes.
4. While apples are cooking, blend eggs and milk, and then add flour. Either whisk or use hand mixer to combine until smooth. If whisked, mixture will have some small lumps. These do not affect the flavor, but may be visible in the final product.
5. When apples and sugar are ready (#3 above), gently pour egg/milk/flour mixture over the top, covering all of the apples. Place in hot oven and bake for 20-30 minutes, until edges are caramelized and rise above the pan. Remove from oven, cut into wedges and serve immediately.
Serves 4 as a main dish, 8 as part of a brunch menu.