Preheat oven to 400°F (200°C).

Carefully cut the spaghetti squash in half lengthwise and spoon out the seeds and stringy pulp.

Drizzle the insides of both squash halves with 1 tbsp extra virgin olive oil and season with salt and black pepper.

Place squash halves cut-side down on a parchment-lined baking sheet and roast for 35-45 minutes until tender.

While squash roasts, heat 1.5 tbsp extra virgin olive oil in a skillet over medium heat. Sauté sliced mushrooms for 5-7 minutes until golden brown and dry.

Stir in minced garlic and cook for 1 minute until fragrant. Add chopped spinach and cook for 2 minutes until wilted.

Lower heat and stir in ricotta cheese, whipped feta, Pecorino Romano, nutmeg, and red pepper flakes until smooth and creamy. Remove from heat.

Flip roasted squash halves over. Scrape flesh with a fork to form spaghetti strands, keeping squash shells intact.

Fold shredded squash strands directly into the skillet with the creamy sauce until well coated.

Spoon filling back into squash shells and top with remaining shredded mozzarella cheese.

Bake for 10 minutes at 400°F, then broil for 1-2 minutes until cheese is golden and bubbly.

Garnish with chopped fresh parsley and extra red pepper flakes before serving.