First of all, La Sonrisa moved about a block and a half. It's now on the corner of Alvarado and Juarez.
Anyway, this all-vegetarian lunch counter has a mixture of Mexican and non-Mexican items. They have things like burritos, empanadas, rieles (similar to empanadas), pizza, spaghetti, salads, various breakfasts and juices. Most things had cheese (and/or egg) though, and things like the burritos and empanadas are pre-made, but they might be willing to make something from scratch if what's already available isn't what you want. Most items (burritos, empanadas, etc.) were between 15 and 25 pesos, and 2 or 3 items would make a complete meal.
Cons: not very vegan-friendly, food is just "ok"...not great