Wash and clean the zucchini and cut into thin spaghetti with a vegetable slicer. Blanch with the peas in boiling salted water for about 2 minutes.
Meanwhile, rinse the basil, shake dry and pluck the leaves. Set aside a few for garnish.
Peel the avocado, cut in half, remove the pit and finely mash the flesh with the basil, cashews, lemon juice, salt, pepper and a little cooking water. Add a little more water if needed and season to taste.
Mix the drained vegetables into the pesto and serve garnished with basil leaves.