Cook the pasta as per package instructions - get a large pot of water boiling, then add the pasta and a pinch of salt. Turn down to medium-high, keeping it to a rolling boil, until just soft - approx 15-20 minutes.

Meanwhile, get a large pan heated to medium-high, and saute the onion, zucchini and carrot with olive oil and a pinch of salt until softened. Add the bell pepper for a few minutes, then the spinach right at the end, to just wilt.

Heat the tomato sauce, if not made fresh, in a small pot.

Once the pasta is cooked, drain it in a colander, serve onto two dishes, top with the sauteed veg, tomato sauce, and the avocado on top. Add a sprinkle of nutritional yeast if you like.