Slow Cooker Cheesy Beef Spaghetti

This Slow Cooker Cheesy Beef Spaghetti is rich, saucy, comforting, and packed with tender pasta, seasoned ground beef, vegetables, and plenty of melted cheese. It is an easy family dinner that combines the flavor of classic spaghetti with the creamy, cheesy texture of a baked pasta casserole.

The beef sauce cooks low and slow with onion, bell pepper, garlic, tomatoes, and Italian seasoning, allowing the flavors to deepen before the pasta and cheese are added near the end. The result is hearty, kid-friendly, and perfect for busy weeknights, potlucks, or Sunday dinner.

Why You Will Love This Recipe

This recipe is easy to prepare ahead and uses affordable ingredients. Browning the beef first gives the sauce better flavor and texture, while the slow cooker handles the long simmering time.

Adding the spaghetti near the end keeps it from becoming overly soft, and a blend of mozzarella, cheddar, and cream cheese creates a rich, creamy finish.

You can also customize the dish with mushrooms, spinach, spicy sausage, extra vegetables, or different cheeses.

Ingredients

For the Beef Sauce

1 1/2 pounds lean ground beef
1 medium yellow onion, diced
1 green bell pepper, diced
3 garlic cloves, minced
1 jar marinara or spaghetti sauce, 24 ounces
1 can crushed tomatoes, 15 ounces
1 tablespoon tomato paste
1 teaspoon Italian seasoning
1 teaspoon garlic powder
1/2 teaspoon onion powder
1/2 teaspoon smoked paprika
1/2 teaspoon black pepper
1/2 teaspoon salt, or to taste
1 teaspoon Worcestershire sauce

For the Pasta and Cheese

12 ounces spaghetti
4 ounces cream cheese, softened and cubed
1 1/2 cups shredded mozzarella cheese
1 cup shredded cheddar cheese
1/2 cup freshly grated Parmesan cheese
1/2 to 1 cup low-sodium beef broth or pasta water, as needed
2 tablespoons chopped parsley, optional

Ingredient Notes

Ground beef: Lean ground beef works best because it produces less grease. An 85/15 or 90/10 blend gives plenty of flavor without making the sauce oily.

Bell pepper: Green bell pepper adds a classic savory flavor. Red or yellow bell peppers can be used for a sweeter taste.

Spaghetti sauce: Use a marinara you enjoy because it forms most of the sauce base. Garlic, basil, or roasted tomato varieties all work well.

Cream cheese: Cream cheese makes the sauce silky and helps bind the pasta and shredded cheeses together.

Spaghetti: The pasta is best cooked separately until just under al dente, then added to the slow cooker near the end. This prevents mushy noodles.

How to Make Slow Cooker Cheesy Beef Spaghetti

Heat a large skillet over medium-high heat.
Add the ground beef, diced onion, and green bell pepper.
Cook for eight to 10 minutes, breaking the beef into small pieces, until browned and the beef reaches 160°F.
Add the minced garlic and cook for 30 seconds.
Drain excess grease.
Transfer the beef mixture to the slow cooker.
Add the marinara sauce, crushed tomatoes, tomato paste, Italian seasoning, garlic powder, onion powder, paprika, black pepper, salt, and Worcestershire sauce.
Stir until everything is evenly combined.
Cover and cook on low for four to six hours or on high for two to three hours.
About 30 minutes before serving, bring a pot of salted water to a boil.
Cook the spaghetti for about two minutes less than the package directions.
Reserve about one cup of pasta water, then drain.
Stir the cream cheese into the hot beef sauce until melted and smooth.
Add the cooked spaghetti to the slow cooker.
Fold gently until the noodles are coated.
Add a splash of beef broth or reserved pasta water if the sauce seems too thick.
Stir in half of the mozzarella, cheddar, and Parmesan.
Sprinkle the remaining cheeses over the top.
Cover and cook on low for another 15 to 20 minutes, until the cheese is melted.
Garnish with parsley and serve hot.

How to Keep the Spaghetti from Getting Mushy

Do not add dry spaghetti at the beginning of slow cooking. Pasta that cooks for several hours will become extremely soft and may absorb too much sauce.

Instead, boil the spaghetti separately until it is slightly firmer than al dente. It will finish cooking after being folded into the hot beef sauce.

Add the pasta only during the final 15 to 20 minutes and avoid leaving the slow cooker on warm for several hours afterward.

How to Get the Creamiest Cheese Sauce

Soften the cream cheese before adding it so it melts evenly into the tomato sauce.

Add the shredded cheeses after the pasta goes into the slow cooker and keep the heat gentle. High heat can cause cheese to become greasy or grainy.

Freshly grated cheese usually melts more smoothly than pre-shredded cheese because packaged varieties often contain anti-caking ingredients.

Easy Variations

For Italian sausage spaghetti, replace half of the ground beef with mild or spicy Italian sausage.

For mushroom beef spaghetti, sauté eight ounces of sliced mushrooms with the onion and pepper.

For extra vegetables, add diced zucchini, carrots, or spinach.

For spicy cheesy spaghetti, add crushed red pepper flakes, cayenne, or pepper Jack cheese.

For extra creaminess, stir in one-half cup sour cream just before adding the pasta.

For a cheesier casserole-style version, transfer the finished spaghetti to a baking dish, top with extra mozzarella, and broil briefly until bubbly and browned.

What to Serve with Cheesy Beef Spaghetti

Garlic bread, cheesy breadsticks, focaccia, or toasted baguette are excellent for soaking up the extra sauce.

For vegetables, serve a Caesar salad, garden salad, roasted broccoli, green beans, asparagus, or zucchini.

The spaghetti is hearty enough to serve as a complete meal, especially for family dinners or potlucks.

Make-Ahead Tips

The beef sauce can be prepared up to two days ahead and refrigerated in an airtight container.

Reheat the sauce in the slow cooker, then cook the spaghetti fresh and add it shortly before serving.

If preparing for a gathering, keep the sauce warm separately and combine it with the pasta and cheese close to mealtime for the best texture.

Storage and Reheating

Store cooled leftovers in an airtight container in the refrigerator for up to three to four days.

The pasta will continue absorbing sauce as it sits, so add a splash of broth, water, or marinara before reheating.

Reheat gently in a covered skillet over medium-low heat or microwave in short intervals.

The dish can be frozen for up to two months, although the pasta will be softer after thawing. Thaw overnight in the refrigerator before reheating.

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