Ingredients

1 medium spaghetti squash (about 2 1/2 lb.)

1 tbsp. neutral oil

1 3/4 tsp. kosher salt, divided

6 oz. broccoli, cut into 1″ florets (about 1 1/4 cups)

1 tbsp. plus 1/4 cup water, divided

3 tbsp. unsalted butter

1/2 yellow onion, finely chopped

3 garlic cloves, minced

1 tbsp. all-purpose flour

1/2 cup whole milk

4 oz. cheddar, shredded, divided (about 1 cup)

Instructions

Step 1: Arrange a rack in the center of the oven and preheat to 400°F (200°C). Cut the spaghetti squash in half lengthwise and scrape out the seeds. Rub the inside of each half with oil and season with 1 tsp. of salt. Place the squash halves cut side down on a baking sheet.

Step 2: Roast the squash for 35 to 45 minutes until tender and browned. Let it cool slightly.

Step 3: While the squash roasts, place broccoli in a medium heatproof bowl. Season with 1/4 tsp. salt and pour 1 tbsp. water into the bowl. Cover and microwave for 1 minute. Stir and continue microwaving in 30-second increments until broccoli is bright green and fork-tender, about 30 seconds to 1 minute more. Uncover and let cool slightly.

Step 4: In a large skillet over medium heat, melt the butter. Add the chopped onion and season with 1/2 tsp. salt. Cook, stirring occasionally, until the onion is tender and sweet, about 7 to 8 minutes. Add minced garlic and cook, stirring, until fragrant, about 1 minute.

Step 5: Stir in the flour and cook, stirring, until a bubbling paste forms on the bottom of the skillet, about 1 minute. Slowly whisk in the milk and remaining 1/4 cup water. Bring to a simmer over medium-high heat and cook, stirring occasionally, until thickened, 1 to 2 minutes. Remove from heat and fold in 3 oz. cheddar until smooth. Taste and season with salt if needed.

Step 6: Using two forks, shred the spaghetti squash strands from the shells. Measure out 3 cups of the strands and add them to the skillet with the cheese sauce. Reserve any leftover squash for another use. Add the steamed broccoli and toss gently to combine and coat everything in the sauce.

Step 7: Spoon the cheesy spaghetti squash and broccoli mixture back into the squash shells. Sprinkle the remaining 1 oz. cheddar on top.

Step 8: Turn on the broiler and place the squash under it. Broil carefully until the cheese on top is melted and blistered, about 1 to 2 minutes. Watch closely to prevent burning. Serve warm.

Tips & Variations

For a smoother sauce, use whole milk, but you can substitute with 2% milk if desired.

Try adding cooked bacon or sautéed mushrooms for extra flavor and texture.

Use sharp cheddar for a more pronounced cheesy taste, or mix cheddar with mozzarella for a gooey finish.

If you don’t have a microwave, steam the broccoli on the stovetop until just tender.

Leftover spaghetti squash can be stored and used in salads or other casseroles.

FAQs

Can I use frozen broccoli instead of fresh?

Yes, you can use frozen broccoli florets. Thaw and drain them well before adding to the sauce to prevent excess water from thinning the cheese sauce.

How do I know when the spaghetti squash is done roasting?

The squash is ready when the flesh is tender and easily pierced with a fork, and the edges are lightly browned. This usually takes 35 to 45 minutes depending on your oven and squash size.