In a large pot with a lid put the olive oil and chopped onions.
Leave it for about five minutes and add the garlic. When you start to smell the garlic, about three minutes, add four zucchinis cut in large pieces, the teaspoon of salt and dried chili. Add the 5 cups of water and cover. Leave for 15 minutes or until the zucchini is fully cooked. Add the basil and the lemon juice.
Blend with a food processor or in the blender.
Try and adjust the flavor if necessary.
Cut in rounds the remaining zucchini and put it in the soup just before serving. Serve with chopped basil leaves, basil flowers and a drizzle of olive oil.