Prepare the Spaghetti Squash:
Preheat your oven to 400°F (200°C).
Slice the spaghetti squash in half lengthwise and remove the seeds with a spoon.
Drizzle the cut sides with olive oil and season with salt and pepper.
Place the squash halves cut-side down on a baking sheet and roast in the oven for 35-40 minutes, or until the flesh is tender and you can easily pull the strands with a fork.
Prepare the Marinara Sauce:
While the squash is roasting, heat a tablespoon of olive oil in a saucepan over medium heat.
Add the minced garlic and sauté for 1-2 minutes until fragrant.
Stir in the marinara sauce, oregano, and red pepper flakes (if using). Let it simmer on low for about 10-15 minutes, stirring occasionally. Adjust seasoning with salt and pepper to taste.
Shred the Squash:
Once the spaghetti squash is done roasting, remove it from the oven and let it cool slightly.
Use a fork to scrape the flesh of the squash into spaghetti-like strands.
Combine and Serve:
Top the spaghetti squash strands with marinara sauce.
Garnish with fresh basil or parsley and sprinkle with Parmesan cheese, if desired.
Serve immediately and enjoy!