Bring a large pot of salted water to a boil. Add whole wheat spaghetti and cook according to package instructions until al dente, about 8-10 minutes. Drain and set aside.
While the pasta cooks, heat olive oil in a large non-stick skillet over medium heat.
Add minced garlic to the skillet and sauté for 1 minute until fragrant, stirring frequently to avoid burning.
Add diced zucchini and red bell pepper to the skillet. Cook for 5 minutes, stirring occasionally, until vegetables begin to soften.
Add halved cherry tomatoes, chopped spinach, dried oregano, dried basil, crushed red pepper flakes, salt, and black pepper to the skillet. Stir to combine.
Pour in the vegetable broth and cook for an additional 3-4 minutes until the spinach wilts and the sauce slightly thickens.
Add the cooked pasta to the skillet and toss well to coat the pasta evenly with the vegetable mixture and sauce.
Remove from heat and sprinkle grated Parmesan cheese over the pasta. Toss gently to combine.
Divide the pasta evenly among four plates and serve immediately.