01 -
Preheat the oven to 200°C. Drizzle 1 tablespoon olive oil over the cut sides of the spaghetti squash halves, season with salt and black pepper, then place cut side down on a baking sheet. Roast for 40 to 45 minutes until tender.
02 -
While the squash roasts, heat the remaining 1 tablespoon olive oil in a large skillet over medium heat. Sauté the finely chopped onion and sliced mushrooms for 5 to 6 minutes until softened.
03 -
Add the minced garlic to the skillet and cook for 1 minute. Stir in the fresh spinach and cook until wilted.
04 -
Pour in the heavy cream and grated Parmesan cheese, stirring continuously until the mixture becomes creamy. Season with salt, black pepper, and red pepper flakes if desired.
05 -
Remove the roasted squash from the oven and use a fork to scrape the flesh into spaghetti-like strands, keeping the strands inside the shells.
06 -
Divide the creamy spinach and mushroom mixture evenly between the squash halves. Top each with shredded mozzarella cheese, then return to the oven and bake for an additional 10 minutes until the cheese is melted and bubbly. Serve warm.