This is the first recipe I post... I hope you enjoy this soup as much as my husband does. I'm from Sonora Mexico, (where this soup is famous) and my nana gave this recipe to my mom and my mom to me. ;) Of course the cheese is important and the best is the "queso regional" but you can substitute it by queso fresco and it works for me... :) as long as you don't use a cheese that melts in strings in the soup...;) for the potatoes I like the California potatoes, or any white potato that is more crunchy... you know how some potatoes are more creamy... pick the crunchy ones. When you buy the queso fresco check the taste, some of them are salty so have in mind that if the cheese you bought is salty you may want to add less salt to the soup. I like the potatoes crunchy, thats why I don't let them boil or cook for long time, so do the potatoes the way you like them -- and the chile tepin is a dry round pea size chili very hot that you can buy in a mexican store, I crush one or two in a paper napkin and add it to the soup, but that is optional. (make sure you don't use that napkin to clean your mouth -- or else -- ).