Roasted Spaghetti Squash with Sage, Zucchini & Parmesan - a cheesy, autumnal Thanksgiving delight

Roasted Spaghetti Squash with Sage, Zucchini & Parmesan

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Roasted Spaghetti Squash with Sage, Zucchini & Parmesan

This flavor-filled dish is perfect either as a vegetarian main or a side dish on Thanksgiving. It's rich and satisfying and chock full of autumnal flavors.
Prep Time1 hour 10 minutes
Cook Time20 minutes
Total Time1 hour 30 minutes
Course: Main Course, Side Dish
Cuisine: American
Servings: 6


  • 1 spaghetti squash, 4-5 pounds
  • ¼ cup olive oil
  • 1 yellow onion, diced
  • 2 large cloves garlic, minced
  • 1 can (28 oz / 796 mL) diced tomatoes, drained
  • 1 medium zucchini, grated
  • 2 tablespoons dried or powdered sage
  • 2 cups (8 oz / 225 grams) shredded mozzarella
  • ½ cup grated Parmesan or Romano cheese


Roast the spaghetti squash

  • Prepare the oven and pans. Preheat the oven to 375°F. Line a baking sheet with parchment paper and set at the ready. Generously butter a 9" x 13" casserole dish and set aside.
  • Prepare the spaghetti squash. Halve the spaghetti squash lengthwise and scrape out the seeds.
  • Bake the spaghetti squash. Place the squash halves face-down on the baking sheets and roast until the skins pierce easily, 45-60 minutes. Remove cooked spaghetti squash from the oven and set aside just until cool enough to handle.
  • Scrape the spaghetti squash into the casserole dish. Scrape the spaghetti squash into the prepared casserole dish and spread it so it covers the dish evenly.

Make the sauce

  • Saute the onions and garlic. Heat the olive oil in a large skillet or small stockpot over medium heat until it shimmers. Add the onion and saute until translucent, 3-4 minutes. Add the garlic and cook until fragrant, 30-60 seconds.
  • Simmer the sauce. Add the drained tomatoes and the zucchini, then lower the heat so that the mixture simmers slowly. Simmer until most liquid has evaporated, 15-20 minutes. Reserve over low heat, if necessary.

Assemble and bake

  • Reheat the oven, if necessary. Heat the oven to 350°F.
  • Assemble the dish. Sprinkle the dried sage over the entire surface of the spaghetti squash, then spoon over all of the prepared sauce. Cover with the mozzarella, then scatter the Parmesan over the top.
  • Bake the dish. Bake until the entire dish is hot and the cheese is bubbly, 15-20 minutes if the squash and sauce were assembled warm, 40-60 minutes if the squash and sauce were assembled cool.
  • Serve. Serve hot. Leftovers can be refrigerated for up to three days.


To make up to two days ahead, roast the spaghetti squash and scrape it into the prepared pan, and make the sauce and set it aside in the refrigerator in its own container. When you want to bake it, assemble it as described just before baking.
If you need to be baking the spaghetti squash at the same time as other dishes, it will bake at any temperature, so don't stress about the bake temperature. Obviously, the cook time will be longer with lower temperatures, but as long as the spaghetti squash ends up so that the skin is able to be pierced easily and the inside is easy to scrape into strands, it's just right.
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