Thrown Together Baked Spaghetti Casserole

Thrown Together Baked Spaghetti Casserole is a like a supreme pizza combined in a casserole. This recipe is perfect for a large crowd!

a cheesy spaghetti casserole with onions, peppers, mushrooms, and more.

Are you looking for a simple spaghetti casserole that tastes great, and is packed full of flavor? Sometimes casseroles can be pretty dull, and they seem to lack a lot of great flavor.

Thrown Together Baked Spaghetti Casserole reminds me of a supreme pizza that got tossed into a bowl of pasta. What creates all of the flavor? Ground beef, onions, olives, bell pepper, and mushrooms make this casserole taste amazing. This casserole gets topped with both Cheddar cheese and Mozzarella cheese.

Spaghetti Casserole for a Crowd

Looking to feed a lot of mouths? Maybe you have a house full of teenage boys, this recipe is perfect for you! This recipe makes up 2 13 x 9-inch pans of pasta! You could serve this dish from a large crockpot if desired. You can mix everything together, and then top with cheese, and place the thermostat on high until the cheese melts, and you can serve up a crowd of people quickly and easily.

pasta casserole with cheese, ground beef, spaghetti sauce, and more.

Dinner done in minutes!

Best of all this filling dish takes no time at all to make. While the pasta is cooking you can make the filling, and about the time the pasta is done cooking, you will be ready to mix it all together. You simply will mix everything together, top with cheese, and then toss this in the oven so the cheese will melt. If you have leftover spaghetti this recipe would be the perfect way to use the leftover pasta!

Pasta casseroles do not get easier than this!

What can you serve with spaghetti casserole?

You might want to serve a salad with this, or perhaps some green vegetables like green beans, or some sauteed zucchini.

A pan of pasta casserole with lots of cheese on top

Love casseroles? Be sure to try some of these cheesy casserole recipes.

Weeknight Ground Beef Casserole
Poppy Seed Chicken
Taco Spaghetti

a cheesy spaghetti casserole with onions, peppers, mushrooms, and more.

Thrown Together Baked Spaghetti Casserole

You can make this spaghetti casserole, it is perfect for when you have a large crowd to feed. 
5 from 1 vote
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Course: Main Course
Cuisine: American
Keyword: Spaghetti Casserole
Prep Time: 10 minutes
Cook Time: 25 minutes
Total Time: 35 minutes
Servings: 12
Calories: 724kcal


  • 2 pounds spaghetti
  • 48 ounces Prego Garden Veggie Sauce
  • 12 ounces shredded Cheddar cheese
  • 12 ounces shredded Mozzarella cheese
  • 4 ounces sliced black olives
  • 1 cup chopped onion
  • 1 sliced green bell pepper
  • 8 ounces sliced mushrooms
  • 2 pounds ground beef


  • Boil spaghetti in salted water according to package directions.
  • Preheat oven to 350.
  • Brown meat. Add onion and bell pepper. Once onion and bell peppers are cooked thoroughly, add sauce, mushrooms, and olives.
  • Let simmer about 10 minutes. Drain noodles and add sauce. Mix well. Pour spaghetti into a casserole dish and sprinkle one layer of each cheese. Let bake for 10-15 minutes or until cheese is melted.

  • Thanks to Prettygorjus for this casserole recipe.


If you like you can make modifications to the recipe.
  • This recipe can be havled
  • Don't have fresh mushrooms? Canned mushrooms work well.
  • You can add any color of bell pepper you desire.


Calories: 724kcal | Carbohydrates: 66g | Protein: 38g | Fat: 33g | Saturated Fat: 15g | Cholesterol: 105mg | Sodium: 1152mg | Potassium: 898mg | Fiber: 5g | Sugar: 8g | Vitamin A: 1040IU | Vitamin C: 17.3mg | Calcium: 401mg | Iron: 4.1mg

About Stephanie Manley

I recreate your favorite restaurant recipes, so you can prepare these dishes at home. I help you cook dinner, and serve up dishes you know your family will love. You can find most of the ingredients for all of the recipes in your local grocery store.

Stephanie is the author of's Dining Out in the Home, and's Dining Out in the Home 2.

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Yes, you CAN make it at home! 
I'll show you how.