Roast the Butternut Squash:

• Preheat your oven to 400°F (200°C).
• Place the squash halves cut-side up on a baking sheet and drizzle with 1 tbsp of olive oil. Season with salt and pepper.
• Roast for 40-45 minutes, or until the flesh is tender when pierced with a fork.

Cook the Sausage Mixture:

• In a large skillet, heat the remaining 1 tbsp of olive oil over medium heat.
• Add the diced onion and sauté for 5-7 minutes until softened.
• Add the minced garlic and cook for 1-2 minutes, until fragrant.
• Add the sausage, breaking it up with a spoon, and cook until browned, about 7-8 minutes.
• Stir in the fresh spinach and cook until wilted, about 2 minutes.
• Season with thyme, sage, red pepper flakes (if using), and additional salt and pepper to taste.
• If using, stir in the breadcrumbs and half of the Parmesan cheese. Mix until well combined.

Stuff the Squash:

• Once the squash is cooked, remove it from the oven and carefully scoop out some of the flesh to create a deeper cavity, leaving about 1/2-inch border.
• Add the scooped squash flesh to the sausage mixture, mashing and stirring to combine.
• Fill the squash halves with the sausage mixture, pressing gently to pack it in.

Bake the Stuffed Squash:

• Sprinkle the remaining Parmesan cheese over the stuffed squash.
• Return the squash to the oven and bake for an additional 10-15 minutes, or until the tops are golden and the cheese is melted.

Serve:

• Let the stuffed squash cool slightly before serving. Garnish with extra Parmesan cheese or chopped parsley, if desired.