In a large stirfry pan, heat oil (use a splash of broth if oil free), leeks or diced onions, garlic, and mushrooms.
Saute for a few minutes until soft and translucent over medium heat.
Add all the 'hard' veggies - cauliflower, broccoli, brussels - stir and saute for 5-7 minutes. Deglaze with a splash of broth or wine as you go.
Add zucchini and meatballs (if using) saute for another 2 or 3 minutes.
Add dry spices - oregano, basil, thyme, any Italian spices plus salt and pepper, red pepper flakes to taste.
Add 4 cups of red sauce - your favourite jarred marinara sauce (2 jars or 1 jar plus 2 cups crushed tomatoes) or try this delicious Rich Red Marinara Sauce recipe. Bring to bubbling over medium-high heat.
Stir in spinach (plus leftover cooked veggies if using).
Reduce heat and let simmer for 5-10 minutes or until meatballs are done*.
If the sauce is too thick, add in some or all of the reserve pasta water to desired consistency.
Taste for seasoning and adjust if necessary.