Preheat oven to 400ºF.

Place the quinoa and 1 1/2 cup of water in a medium saucepan. Bring to a boil, then reduce heat to a simmer, cover, and cook for about 12 minutes, or until the quinoa is tender and most of the water is absorbed. Remove from heat and let the quinoa sit, covered, for 5 minutes. Strain any excess liquid.

While the quinoa is cooking, scoop the seeds out of the zucchini and discard them. Place the zucchini halves in a large baking dish that's been coated with oil or cooking spray.

Stir the tomato sauce, garlic, herbs, onion powder, and pepper flakes into the quinoa. Season with salt to taste.

Divide the quinoa mixture into the zucchini halves, then top with the cheese. Bake for 20-25 minutes, or until the zucchini is tender and the cheese is just beginning to brown. Garnish with additional fresh basil and serve.