This Cheesy Garlic Parmesan Spaghetti Squash is a beautifully simple dish that brings together tender roasted squash, aromatic sautéed onions and garlic, melted butter, fresh parsley, and a generous finish of Parmesan cheese. It is naturally light, comforting, and wonderfully versatile, offering a satisfying texture that resembles pasta strands while remaining much lower in carbohydrates. Every step of the preparation highlights the squash’s natural sweetness, which pairs perfectly with the savory garlic and the nutty depth of Parmesan. The result is a warm and inviting dish that works equally well as a flavorful side or as a light main course.
Ingredients
- 3 pounds spaghetti squash
- 4 tablespoons unsalted butter
- 1/4 cup minced red onion
- 4 cloves garlic, finely minced
- 1/2 teaspoon salt
- 1/4 cup chopped parsley
- 1/2 cup freshly grated Parmesan cheese
Instructions
- Preheat the oven
Begin by heating your oven to 400°F (200°C). Allow it to fully reach temperature so the squash cooks evenly and develops a soft interior. Place a baking sheet on your counter, ready to hold the whole squash. - Prepare the spaghetti squash
Take the whole squash and, if necessary, quickly rinse the outer skin to remove any dirt. Dry it well so it is easier to handle. Using a sharp knife, carefully pierce several small holes all around the squash. This step is essential, as the holes allow steam to escape during roasting. Without them, the squash can build pressure inside, which may cause it to burst. The piercing should be deep enough to penetrate the skin but not so deep that the knife goes into the center. - Roast the squash
Place the whole, pierced squash onto your baking sheet. Transfer it to the preheated oven and roast for about 1 hour. During this time, the squash slowly softens, and the interior transforms into long, tender strands. You’ll know it is fully cooked when a fork or knife can slide into the skin with little resistance and the exterior begins to feel slightly soft when pressed with an oven mitt. - Let it cool briefly
Remove the baking sheet from the oven and allow the squash to rest for about 15 minutes. This cooling period is important because the squash will still be very hot inside. Allowing it to rest makes it safer to handle while keeping the strands warm and easy to separate later. - Cut the squash and remove the seeds
Place the slightly cooled squash on a stable cutting board. With a sharp knife, slice it in half lengthwise from top to bottom. Once open, use a spoon to scoop out the seeds and the surrounding soft pulp. Remove these completely so that only the firm, cooked flesh remains. - Scrape the flesh into strands
Use a fork to scrape the inside of each squash half. As you drag the fork from one end to the other, the flesh naturally separates into long, noodle-like strands. Continue scraping until the squash shells are nearly empty and you have collected all the strands in a large bowl. They should feel tender but still have a slight firmness, similar to perfectly cooked pasta.
- Prepare the garlic-onion butter
Place a large sauté pan over medium heat and add the butter. Let it melt slowly, tilting the pan to coat the bottom evenly. Add the minced red onion and cook for about 3 to 5 minutes, stirring occasionally, until the onion softens and becomes slightly translucent. It should release a mild sweetness without browning.
Add the minced garlic and cook for another 30 seconds. The garlic should become fragrant quickly, infusing the butter with a rich aroma, but it should not darken, as this would create a bitter taste. - Combine the squash with the aromatics
Add the warm spaghetti squash strands directly into the pan. Toss them gently but thoroughly so that every strand is coated in the buttery mixture. Sprinkle in the salt and continue mixing until the seasoning is evenly distributed. The strands should look glossy and intertwined with bits of onion and garlic throughout. - Finish with parsley and Parmesan
Add the chopped parsley and the freshly grated Parmesan cheese. Incorporate them slowly, allowing the warmth of the squash to soften the cheese so it lightly melts and clings to the strands. The parsley adds freshness and color, balancing the richness of the butter and Parmesan.
Taste a small portion and adjust the seasoning if needed, adding a bit more salt to enhance the flavors. Once everything is balanced, remove the pan from the heat. - Serve warm
Transfer the squash to a serving bowl or platter. It should appear well-mixed, with vibrant green parsley, subtle purple onion pieces, and a delicate coating of melted Parmesan throughout. Serve immediately while it is warm and tender.