In a large saucepan, heat the oil on medium heat and sauté the onion and garlic for about 5 minutes. Add the zucchini and the broth, cilantro and cayenne. Cover and simmer 10 minutes, until the zucchini is soft.
Puree in a blender, or with an immersion blender. Season to taste with sea salt and more cayenne.
Serve garnished with garnishes of crumbled cheese, pumpkin seeds or slices of avocado, if you wish.
Notes
Cotija cheese is a Hispanic-style cheese--somewhat salty and doesn’t really melt--you may substitute any cheese you want. Vegans--just skip the cheese.