Bring a large pot of salted water to a boil and add the pasta, stirring occasionally until pasta is al dente.
Meanwhile, heat a large skillet over medium-high heat. Add olive oil.
When olive oil is fragrant, add onion, garlic, zucchini, mushrooms, thyme, a pinch of salt and pepper, and chili flakes (if using). Stir vegetables and sauté 4-6 minutes, until veggies are tender.
While the vegetables are cooking, make a slurry by whisking the cornstarch into the milk.
When veggies are tender, add the milk and cornstarch slurry and broth and stir. The slurry will thicken quickly as it heats.
Add lemon zest, lemon juice, and parmesan and stir.
Before draining pasta, reserve 1/4 cup of the pasta cooking water. Then drain pasta and add pasta to skillet with the veggies and sauce. Stir to evenly coat the pasta in the sauce.
If needed, add 2 tablespoons to the full 1/4 cup of pasta water until you've got the saucy texture you want.
Garnish with chopped parsley and grated parmesan, serve, and enjoy!
Notes
Nutrition information calculated using chickpea pasta, skim milk, low sodium chicken broth, and includes garnish.