1.
Preheat oven to 425 degrees F.
2.
Crumble sausage into a 10-inch cast iron skillet and set over medium heat. Cook until sausage is thoroughly browned, then pour off excess grease and transfer to plate.
3.
Add butter to the skillet. When butter melts, add apples and brown sugar. Cook for about 8 minutes to soften.
4.
While apples are cooking: beat eggs with milk, flour, sugar, and salt in a bowl. It helps to use an electric hand mixer to make this the smoothest it can be. Pour into the skillet over the apples.
5.
Top the egg mixture with sausage and cheese. Bake for about 20 minutes, until pancake rises and browns. Serve.