Best authentic food in the city?

Okay I know there’s so many ‘best xyz food in the city posts’… but I’m looking for authenticity and/or quality for a decent price. Any type of food. I have a friend coming to town who loves smaller, often family-run. Or hole in the wall places that usually are way more authentic than big name restaurants and I want to find a great place to take him to dinner that maybe isn’t the classic SF restaurant experience.