- 1 tablespoon olive oil
- 1 pound bulk Italian sausage
- 2 tablespoons sausage drippings
- 2 tablespoons margarine
- 2 apples, cored and sliced
- 1 large onion, sliced
- salt and ground black pepper to taste
- 1 teaspoon dried oregano
- 1 tablespoon all-purpose flour
- 1 cup water
- 3 cups prepared mashed potatoes
- 1 tablespoon melted margarine
- Preheat oven to 350 degrees F (175 degrees C).
- Grease a 2-quart casserole dish.
- Heat olive oil in a skillet over medium heat; cook and stir Italian sausage until browned and crumbly, about 10 minutes. Use a slotted spoon to transfer sausage to prepared casserole dish. Drain drippings and reserve 2 tablespoons drippings in the skillet.
- Melt 2 tablespoons margarine in a separate skillet over medium heat; cook and stir apple and onion slices until tender, about 8 minutes. Place apple and onion in casserole dish with sausage.
- Lightly stir sausage, apple, and onion together; season with salt, black pepper, and oregano.
- Brown flour in reserved drippings in skillet over medium heat. Whisk water into flour until thick gravy forms, about 3 minutes.
- Pour gravy over sausage mixture in the casserole dish; spread mashed potatoes over the top with a spoon, creating peaks. Lightly brush mashed potatoes with 1 tablespoon melted margarine.
- Bake in the preheated oven until the potatoes are lightly browned and the sausage mixture is bubbling, about 30 minutes.