Preheat the oven to 350 degrees F.
In a large cold skillet, arrange the sausage slices in 1 layer. Set over medium-high heat, and cook, turning the slices once or twice until they are crisp and nicely browned on both sides, about 10 minutes. Remove from the heat and set aside.
In a 2-quart casserole, arrange a layer of about 1/4 of the sausage slices. Cover the sausage with a layer of about 1/4 of the apple slices. Sprinkle lightly with cinnamon. Continue in this manner to make 4 layers, ending with the apple slices.
Stir the Calvados into the skillet in which the sausage was browned, scraping up any crusty, brown bits that cling to the bottom of the pan. Stir in the cream until well blended, Pour this mixture evenly over the casserole.
Cover, and bake for 1 hour until the apples have cooked down and the mixture is bubbling. Sprinkle with parsley before serving.
Recipe courtesy of Joseph Bernard, The New York Cabbie Cookbook, Running Press, 2003