01 - Bring a large pot of salted water to a boil. Cook pasta according to package directions until al dente. Reserve 1/2 cup pasta water, then drain and set aside.
02 - While pasta cooks, heat olive oil in a large skillet over medium heat. Add onion and sauté 2-3 minutes until softened.
03 - Add garlic to skillet and cook 30 seconds until fragrant, being careful not to burn.
04 - Stir in zucchini and cook 4-5 minutes until just tender but still slightly crisp.
05 - Add cherry tomatoes, Italian herbs, red pepper flakes, salt, and pepper. Cook 4-5 minutes, stirring occasionally, until tomatoes soften and release their juices.
06 - Toss in spinach if using and cook 1-2 minutes until wilted.
07 - Add drained pasta to skillet. Toss everything together, adding reserved pasta water as needed to create a silky sauce.
08 - Remove from heat. Stir in fresh basil and sprinkle with Parmesan cheese if desired. Serve immediately, garnished with extra basil and a drizzle of olive oil.