Preheat your oven to 400°F (200°C).
Carefully slice the spaghetti squash in half lengthwise and scoop out all the seeds.
Prick the outer skin of each squash half a few times with a fork to allow steam to escape during cooking.
Drizzle a little olive oil on the cut sides of the squash. Sprinkle with salt and pepper. Place the squash cut-side down on a parchment paper-lined baking sheet.
Bake for about 35 minutes, or until the squash is tender when pierced. Remove from the oven, flip the halves over, and let them cool slightly while you prepare the creamy sauce.
In a large skillet, melt the butter and 1 tablespoon of olive oil over medium-low heat. Add the minced garlic and sauté gently for about 10 seconds until it smells fragrant, being careful not to brown it.
Stir in the chicken broth and mascarpone cheese until smooth. Season with a little more salt and pepper to your taste.
Once the spaghetti squash is cool enough to handle, use a fork to gently scrape out the strands, creating a noodle-like texture.
Add the spaghetti squash strands to the skillet with the sauce, along with the fresh parsley and optional red pepper flakes. Toss everything together until well combined and heated through.
Finally, stir in the freshly grated Parmesan cheese until it melts into the creamy squash. Serve immediately, garnished with extra Parmesan and fresh parsley if you like. Enjoy your healthy, flavorful dish!