In a large soup pot or dutch oven, add the oil and butter. Once melted add the onions and a generous pinch of kosher salt. Saute for 7-10 mins until onions are soft and translucent. Add green chiles, tomatillos, more salt and saute for another 10 mins or so. If you're using tomatillo salsa, add that later with the tomatoes. Add the garlic and saute for another minute or so until fragrant. Next add the tomatoes, water, better-than-bouillon and spices. Bring to a low boil and simmer for at least 20 minutes, up to one hour. Taste for salt. In a small bowl, add 1.5 cups water and the garbanzo bean flour and whisk until smooth, this takes a few minutes. If there are lumps, just let sit for a few minutes and whisk again. On a low boil, add the flour slurry slowly, stirring constantly. Let simmer and taste again for salt. This tastes better and gets spicier the next day! Smother burritos liberally!