The 24th and Mission location is where I managed to snag a quesadilla 4x the size of my head -- the quesadilla para dos is actually more like quesadilla para ocho! Oh, and their green sauce is amazing, especially at 3 AM.
This is one of those places that if you blink, you'll miss it. Seriously awesome Mexican pastries. And for cheap, too! 30, 50 and 80 cents depending on what you get. I suggest you go big and go for their amazing 80 cents bread pudding ;)