Preheat your oven to 400°F (200°C).

Carefully cut the spaghetti squash in half lengthwise and scoop out the seeds.

Drizzle the insides with olive oil and sprinkle with salt and pepper.

Place the squash halves cut-side down on a baking sheet lined with parchment paper and roast for about 30-40 minutes, or until the flesh is tender.

While the squash is roasting, heat a large skillet over medium heat.

Add the ground turkey (or beef) and cook until browned. Drain excess fat if necessary.

Add the diced onions and bell pepper to the skillet and sauté for about 5 minutes until softened.

Stir in the minced garlic and chopped spinach, cooking until the spinach wilts.

Sprinkle in the Italian seasoning, salt, and pepper. Pour in the marinara sauce and stir to combine well, cooking for an additional 5 minutes.

Once the squash is roasted, use a fork to scrape out the flesh, creating spaghetti-like strands, and mix these strands into the vegetable and meat mixture.

Stuff the squash shells with the filling, packing it nicely.

Top generously with shredded mozzarella cheese.

Return the stuffed squash to the oven and bake for another 10-15 minutes or until the cheese is melted and bubbly.

Remove from the oven, garnish with fresh herbs, and serve warm.