Cook the pasta in well‑salted water until al dente. Reserve 1/2 cup of pasta water.
Heat olive oil in a large pan over medium heat. Add the garlic and sauté until fragrant.
Add the cherry tomatoes, zucchini, and bell pepper. Cook until the vegetables are tender but still bright.
Stir in the spinach and let it wilt.
Season with salt, pepper, and red pepper flakes.
Add the cooked pasta to the pan and toss everything together, adding a splash of pasta water if needed.
Stir in Parmesan and lemon juice. Taste and adjust seasoning.
Serve warm with extra Parmesan or fresh basil if desired.