Preheat oven to 400°F (200°C).
Cut the spaghetti squash in half lengthwise and scoop out the seeds.
Drizzle 1 tablespoon of olive oil over the cut sides of the squash and season with kosher salt and black pepper.
Place the squash halves cut-side down on a baking dish and roast for 40 minutes, or until tender.
While the squash roasts, in a mixing bowl combine cherry tomatoes, roasted red peppers, minced garlic, remaining 2 tablespoons olive oil, Italian seasoning, kosher salt, and pepper.
After 40 minutes, remove the squash from the oven and carefully flip cut-side up.
Nestle the block of feta cheese in the center of the squash halves.
Spoon the tomato and pepper mixture around and over the feta.
Return the dish to the oven and bake for an additional 10 minutes, or until the feta is soft and slightly golden.
Remove from oven and use a fork to scrape the flesh of the spaghetti squash, mixing it gently with the melted feta and tomato mixture to create a creamy sauce.
Sprinkle chopped fresh basil on top before serving.