Active time:

20 min.

Total time:

1 hour, 35 min.


Serves 12 (serving size: 1 1/3 cups) 
Our Spaghetti Squash Casserole has all the goodness of a cheesy pasta bake, and therefore the absence of pasta makes room for many nutrients. The beef, marinara sauce, mozzarella, and parmesan keep that classic casserole taste intact, while the squash “noodles” delay nicely and don’t water out. The flavors keep this family-friendly, but it’s especially great for anyone trying to avoid gluten.


  • 2 (2 1/2-lb.) spaghetti squash, halved lengthwise and seeded
  • 4 tablespoons olive oil, divided
  • 2 1/2 teaspoons kosher salt, divided
  • 1 teaspoon black pepper, divided
  • 1 pound 90/10 lean ground beef
  • 2 cups chopped yellow onion (from 1 large onion)
  • 6 medium garlic cloves, chopped (2 Tbsp.)
  • 1 (24-oz.) jar marinara sauce
  • 1 pound low-moisture part-skim mozzarella cheese, shredded (about 4 cups), divided
  • 2 ounces Parmesan cheese, grated (about 1/2 cup), divided
  • 2 tablespoons chopped fresh flat-leaf parsley

How to Make It

Step 1

Preheat oven to 425°F. Rub cut sides of squash evenly with 3 tablespoons of the oil; sprinkle with 1 teaspoon of the salt and 1/2 teaspoon of the pepper. Arrange, cut sides down, on a baking sheet lined with parchment paper. Roast in preheated oven until easily pierced with a knife, 40 to 45 minutes. Remove from oven. Reduce oven temperature to 350°F. Let squash cool 10 minutes.

Step 2

While squash cools, heat remaining 1 tablespoon oil during a large skillet over medium-high. Add beef; cook, stirring often, until just browned, 4 to five minutes. Add onion and garlic; cook, stirring often, until softened, 3 to 4 minutes. Stir in marinara and remaining 1 1/2 teaspoons salt and 1/2 teaspoon pepper. Cook, stirring constantly, 1 minute. Remove from heat.

Step 3

Using a fork, scrape cooled squash flesh into large strands, and place during a large bowl. Discard shells. (Strands could also be stored in an airtight container in refrigerator up to 2 days.) Add beef mixture to squash in bowl; toss to mix . Stir in half (about 2 cups) of the mozzarella and half (about 1/4 cup) of the Parmesan.

Step 4

Spoon mixture into a 13- x 9-inch baking dish. Sprinkle evenly with remaining 2 cups mozzarella and 1/4 cup Parmesan. Bake at 350°F until cheese is lightly browned, 30 to 35 minutes. Let cool 5 minutes. Sprinkle with parsley. Serve.