01 - Preheat oven to 350°F (175°C). Lightly grease a large ovenproof skillet or baking dish (10–12 inch diameter).
02 - In a skillet over medium heat, melt 2 tablespoons of butter. Add the diced apples, brown sugar, cinnamon, nutmeg, and lemon juice. Sauté for 5 to 7 minutes, or until the apples begin to soften. Stir in the cornstarch and continue to cook for 1 minute more, until the mixture has thickened. Remove from heat and set aside.
03 - In a large mixing bowl, whisk together the eggs, whole milk, heavy cream, granulated sugar, vanilla extract, cinnamon, and salt until well combined.
04 - Add the cubed bread to the egg mixture and toss gently to ensure all pieces are coated. Allow the bread to soak for approximately 5 minutes.
05 - Arrange half of the soaked bread cubes in the prepared skillet. Evenly distribute half of the prepared apple filling over the bread. Add the remaining soaked bread cubes, followed by the rest of the apple filling.
06 - In a medium bowl, combine the all-purpose flour, brown sugar, cinnamon, and salt. Add the chilled, cubed butter. Use a pastry blender or your fingertips to cut the butter into the dry ingredients until the mixture forms coarse crumbs.
07 - Evenly sprinkle the crumb topping over the assembled skillet. Place the skillet in the preheated oven and bake for 30 to 35 minutes, or until the dish is puffed, golden brown, and a knife inserted into the center comes out clean.
08 - Allow the skillet to cool for 10 minutes before serving. Serve warm. Optional accompaniments include maple syrup or a scoop of vanilla ice cream.