This main course spaghetti squash dish is rich, hearty, and it delivers a ton of delicious flavor from fresh, simple, ingredients.
Preheat the oven 400° F and adjust a rack to the center.
Cut about an inch off of the stem ends of the squash. Place them squash on their bases you’ve just made, and use a large Chef’s knife to slice down the center, vertically. Now scrape out the seeds with a metal spoon. Drizzle a bit of olive oil on a baking sheet and place all 4 halves of the squash on top, round side up. Roast in the preheated 400° F oven until they’re very soft, about 40 minutes.
While the squash is cooking, squeeze the sausages out of their casings, and add them to a large sauté pan, and break them into bite-sized pieces. Turn the heat to medium and sauté until it’s cooked through. If the sausage doesn’t have enough fat to keep it from sticking, add olive oil to the pan.
Add the onions and garlic to the sausage and cook until the onions are soft and becoming golden, about 10 minutes.
Pour the vermouth in the pan and use a flat-edged — preferably wooden — spatula to deglaze the pan, scraping any bits of food off the bottom of the pan and then mixing them back into everything else.
Once the vermouth has cooked off, add the nutmeg, tomato sauce and spinach. Stir until the spinach has totally wilted. Season generously to taste with salt and pepper. (Here’s How to Season to Taste.)
After 40 minutes, or when all of the squash are quite soft, use kitchen tongs to remove them from the oven, and turn the temperature down to 375° F.
Use kitchen tongs to turn the squash over to let them cool for a few minutes. Use a fork to very gently pull the flesh away from the skin. It will naturally come off in strings. Add the squash “strings” to a very large mixing bowl, and place the now empty squash skins, round sides down, back on the baking sheet.
Add the spinach-sausage mixture to the large bowl of spaghetti squash, along with about 2 3/4 cups of the cheese. Mix very well, and season again with salt and pepper to taste — if necessary. (Here’s how.)
Divide the mixture between the 4 squash halves and top each on with a bit of the remaining 1/4 cup of cheese. Place in the 375° F oven for 10 to 15 minutes, to melt the cheese and to be sure everything is heated through.
You can spoon out the mixture to serve, or cut the entire squash halves into slices. Whatever suits you.