
In a large, thick-bottomed pot over medium-high heat, add the olive oil. When the oil is hot, add the garlic, onions, and chile (if using). Sauté for a few minutes along with the salt. Keep going until the onions soften up and start to take on a bit of color. Stir in the potatoes and zucchini. Add the broth (or water and bouillon powder). The broth should barely cover the other ingredients. Bring to a gentle simmer and cook until potatoes are soft throughout, 10-15 minutes.
Stir in the spinach, and wait for it to wilt, just ten seconds or so. Now stir in the cilantro. Remove from heat. Puree with a hand blender until smooth, or alternately, transfer to a high-speed blender. Taste and add more salt to taste if needed. Finish with a drizzle of olive oil, any toppings, and serve.