This is a delicious one-dish meal, and it's so easy to prepare. It's a great way to use leftover corned beef, or use canned corned beef in the recipe. The recipe calls for Swiss cheese, but a combination of Swiss and cheddar or a cheddar jack blend would work as well.
The buttery rye bread crumb topping is the perfect finishing touch, and the casserole can be made a day in advance.
- 3 cups diced leftover corned beef
- 4 tablespoons butter (divided)
- 1 cup chopped onion
- 1/2 green bell pepper, chopped
- 1/2 teaspoon dried leaf thyme
- 2 tablespoons spicy mustard or grainy mustard
- 16 to 24 ounces hash brown potatoes (thawed, about 5 to 6 cups)
- Kosher salt and freshly ground black pepper
- 1 1/2 cups shredded Swiss cheese
- 1 cup breadcrumbs (preferably rye bread)
- Heat oven to 375 F (190 C/Gas 5). Grease a 9-inch square baking dish or a 2 1/2-quart casserole.
- Melt 2 tablespoons of the butter in a large skillet over medium heat. Add the chopped onion and bell pepper and cook, stirring, until tender. Add the thyme and diced corned beef and then saute for 2 to 3 minutes, until hot. Stir in mustard and set aside.
- Press the thawed potatoes lightly in the baking dish. Sprinkle the potatoes lightly with kosher salt and pepper, and then top the potatoes with about half of the shredded Swiss cheese; spoon the corned beef mixture over the cheese. Sprinkle remaining cheese over the corned beef mixture.
- Put the rye bread crumbs in a small bowl. Melt the remaining 2 tablespoons of butter. Drizzle the butter over the breadcrumbs and mix well with a fork. Sprinkle the crumbs evenly over the casserole.
- Bake the casserole for 30 to 40 minutes, or until hot and the topping is lightly browned.
Tips and Variations
- Make Ahead - Prepare the casserole and top it with the cheese. Cover the baking dish with foil and refrigerate the casserole. Take it out of the refrigerator about 30 minutes before baking. Prepare the breadcrumbs and sprinkle over the top. Bake as directed. It might take a bit longer. The safe minimum temperature for casseroles is 160 F (71.1 C) on a food thermometer.
- Instead of plain hash browns, use O'Brien style potatoes with peppers and seasonings.