Leftover Roast Beef Casserole

Leftover roast beef casserole recipe in a dish with a serving spoon

The Spruce 

Prep: 15 mins
Cook: 35 mins
Total: 50 mins
Servings: 4 servings
Nutritional Guidelines (per serving)
374 Calories
16g Fat
43g Carbs
15g Protein
See Full Nutritional Guidelines Hide Full Nutritional Guidelines
Nutrition Facts
Servings: 4
Amount per serving
Calories 374
% Daily Value*
Total Fat 16g 21%
Saturated Fat 9g 43%
Cholesterol 42mg 14%
Sodium 2423mg 105%
Total Carbohydrate 43g 16%
Dietary Fiber 5g 19%
Protein 15g
Calcium 313mg 24%
*The % Daily Value (DV) tells you how much a nutrient in a food serving contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.
(Nutrition information is calculated using an ingredient database and should be considered an estimate.)

There are lots of recipes for leftover roast beef, and many ways to use it. Make a cottage pie, use it in sandwiches, heat it in your favorite stroganoff sauce, or slice the beef into strips and add it to a tossed salad. Or turn it into a whole new dinner and make this leftover roast beef casserole instead.

This casserole is simply a mixture of cooked roast beef, gravy, and vegetables. A cheese topping completes the layers. It's a great spur-of-the-moment dish to fix and serve with boiled or mashed potatoes. It's excellent over rice or noodles as well.

For this recipe, you can either use canned or prepared beef gravy, or make your own from scratch using a roux; don't worry if you don't have the pan drippings from the roast, as you don't need them.


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  • 1 (10-ounce) package peas and carrots (frozen, about 1 1/2 cups)
  • 1 cup pearl onions (frozen)
  • 2 cups diced leftover roast beef (cooked, 1/4-inch to 1/2-inch dice)
  • 1 cup beef gravy (homemade, canned, or made from dry mix)
  • 1/2 cup shredded sharp cheddar cheese

Steps to Make It

  1. Gather the ingredients.

    Leftover roast beef casserole recipe ingredients
    The Spruce 
  2. Heat the oven to 350 F. Lightly grease a 1 1/2-quart to 2-quart casserole dish or spray it with nonstick cooking spray.

    A blue casserole dish on a table
    The Spruce
  3. In a medium saucepan, cover the frozen peas, carrots, and pearl onions with water. Bring to a boil.

    Carrots, peas and onions in a pot with water
    The Spruce
  4. Reduce the heat and simmer for about 5 minutes or until the vegetables are tender.

    Cooked onions, peas, and carrots in a saucepan
    The Spruce
  5. Drain the vegetables thoroughly and transfer them to a large bowl.

    Drained and cooked peas, carrots, and pearl onions
    The Spruce
  6. Combine the roast beef with the gravy and then add it to the bowl with the vegetables. Mix well.

    Mixed vegetables with leftover beef
    The Spruce 
  7. Transfer the beef and vegetable mixture to the prepared casserole, spreading it out evenly, and top with shredded cheddar cheese.

    Leftover roast beef casserole sprinkled with cheddar cheese
    The Spruce
  8. Bake in the preheated oven for 25 to 35 minutes, or until the filling is bubbling and the cheese has melted.

    Baked roast beef casserole with vegetables and cheese
    The Spruce
  9. Serve and enjoy.

    Serving roast beef casserole topped with melted cheese
    The Spruce

Glass Bakeware Warning

For premade casseroles or leftovers that are in a glass baking dish and have been refrigerated, do not place directly into a hot oven as the glass can shatter. Instead, place any cold glass bakeware into a cold oven to warm up while it preheats. Or, allow the bakeware to rest outside of the fridge for 30 minutes to reach room temperature while the oven preheats.

Recipe Variations

  • If you don't have leftover roast beef, use thick-sliced deli roast beef or diced raw meat. Stir-fry the raw beef before combining it with the gravy.
  • Swap the leftover roast beef for browned ground beef in the recipe.
  • Diced leftover lamb or roast pork are some other excellent alternatives, along with beef or pork gravy.
  • The vegetables are interchangeable as well. You can use frozen mixed vegetables, peas, green beans, or diced carrots. If you don't have pearl onions, use 1 medium onion, halved and sliced.

How to Store and Freeze Leftover Beef Casserole

Leftover casserole will keep in the fridge for 3 to 4 days in an airtight container. Reheat in the microwave or a low oven until completely hot.

For longer storage in the freezer, the casserole should keep for up to 3 months if frozen in an airtight container or zip-close plastic bag.