Sausage Peppers Squash Casserole

The first time I made this casserole, my skeptical husband took three servings before asking what kind of pasta we were eating. When I told him it was squash, he literally stopped mid-bite with this hilarious look of betrayed confusion on his face.

Last winter, my neighbor Sarah came over during a snowstorm and we ended up improvising this with whatever we had in the fridge. She still texts me about that casserole whenever it snows.

Ingredients

• 1 large spaghetti squash: Look for one that feels heavy for its size with a hard, unblemished skin. The weight means more flesh to transform into those pasta-like strands.
• 12 oz Italian sausage: I prefer removing the casings so it crumbles beautifully into the sauce. Hot sausage adds a lovely kick, but mild works perfectly for sensitive palates.
• 1 red and 1 yellow bell pepper: Using both colors makes the dish so much more inviting. Slice them thin so they soften nicely during cooking.
• 1 small yellow onion: Thinly slice it rather than chopping. The longer strands mimic the squash texture and look gorgeous throughout.
• Marinara sauce: A good quality sauce makes all the difference here. Taste it first and adjust seasonings if needed.
• Shredded mozzarella and grated Parmesan: The mozzarella creates those irresistible stretchy pulls, while Parmesan adds that salty, nutty depth that makes the whole dish sing.

Instructions

Roast the squash:

Cut that stubborn spaghetti squash in half lengthwise (stab it a few times first if its being difficult) and scoop out the seeds. Brush the cut sides with olive oil, season generously with salt and pepper, then place cut side down on a parchment lined baking sheet. Roast at 400°F for 35 to 40 minutes until a fork easily pierces the skin and the flesh pulls away in strands.

Prepare the sausage and vegetables:

While the squash roasts, heat olive oil in a large skillet over medium heat. Add the sausage and break it up with a wooden spoon as it browns, about 6 or 7 minutes. Toss in the sliced peppers and onions, sautéing for 5 minutes until theyre softened and fragrant. Stir in the garlic, oregano, basil, and red pepper flakes for one final minute of cooking.

Create the sauce:

Pour in the marinara sauce and let everything simmer together for 5 minutes. This step lets all those flavors become best friends.

Assemble the casserole:

Once the squash is cool enough to handle, use a fork to scrape the flesh into strands. Reduce the oven temperature to 375°F and combine the squash strands with the sausage mixture, half the mozzarella, and half the Parmesan in a large bowl. Transfer everything to a greased baking dish and top with the remaining cheese.

Bake to golden perfection:

Bake uncovered for 15 to 20 minutes until the cheese is bubbling and starting to turn golden in spots. Let it rest for 5 minutes before serving, which gives it time to set slightly and makes serving much easier.

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This recipe became my go to when my mom started watching her carb intake but still wanted comforting Italian flavors. Now she requests it more than I do.

Make Ahead Magic

You can absolutely assemble this entire casserole a day before baking. Just cover it tightly and refrigerate, then add 5 to 10 minutes to the baking time since it will be cold. The flavors actually develop even more this way.

Vegetarian Swaps

Plant based sausage works remarkably well here, or try sautéed mushrooms with extra vegetables. You might want to bump up the dried herbs to compensate for losing that Italian seasoning from the sausage.

Serving Suggestions

A simple green salad with balsamic vinaigrette cuts through the richness beautifully. If youre not strictly low carb, some crusty garlic bread never hurt anyone.

• Top with fresh basil just before serving for a pop of color and fresh flavor
• Let it rest the full 5 minutes or it will be too loose to serve neatly
• Store leftovers in the refrigerator for up to 4 days

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Theres something deeply satisfying about serving a dish that tastes indulgent while secretly being so wholesome. Watch peoples faces when they realize theyve been fooled by a vegetable.

Recipe Questions & Answers

→ How do I prepare spaghetti squash for this dish?

Cut the squash in half lengthwise, remove the seeds, brush with olive oil, season, and roast cut-side down until tender. Then scrape out the flesh into strands.

→ Can I use a different type of sausage?

Yes, you can substitute with turkey, chicken, or plant-based sausage for a variation in flavor or dietary preference.

→ What is the best way to sauté the vegetables?

Sauté sliced bell peppers and onions in olive oil over medium heat until softened, then add minced garlic and herbs for additional aroma and taste.

→ How do I ensure the casserole is bubbly and golden on top?

Top the mixture with mozzarella and Parmesan cheese before baking at 375°F (190°C) for 15–20 minutes until the cheese is melted and golden.

→ Can this dish be made ahead of time?

Yes, assemble the casserole in advance and refrigerate, then bake just before serving to retain freshness and flavor.