Chop the courgette squash and onion into small pieces. Crush the garlic cloves.
In a frying pan, fry onion and garlic until lightly browned, then add the courgette. Stir for a couple minutes and remove from heat.
If you have time you can salt the courgette and place in a colander and leave for 30 minutes or so to remove some of the water, then rinse and pat dry before frying, but this is not essential. If you do this you may need to add a few teaspoons of water if the sauce becomes too dry and stiff when blending it.
Shell the pistachio nuts, then put them in a food processor to blend until chopped into little pieces. Next add the onion, garlic, courgette, optional vegan parmesan to the food processor. Salt and pepper to taste. Whizz content in the food processor, stopping periodically to add olive oil and basil (and optional oregano) to taste, until you get a pesto consistency that will easily coat your hot drained pasta.
Stir mixture into hot, drained pasta and serve.

1 medium sized courgette squahs/zucchini
1 medium onion
2 cloves garlic
3-4 tablespoons olive oil plus extra for frying
3-4 tablespoons vegan parmesan 'parmazano' (optional)
25-40 gram pistachios nuts (unshelled weight)
salt and pepper
basil, to taste
oregano, to taste (optional)