Before Xoco opened in a cramped space on North Clark Street, it wasn't necessarily a given that Chicago craved chef-y Mexican tortas. Instead of gussying up the classic street food sandwich by adding dozens of oddball ingredients, Rick Bayless kept toppings to a minimum. What he did do was make sure each component was of exceptionally high quality. That starts with the bread, which is given a blast in the wood-fired oven for a smoky aroma and crackly crust. Though all the tortas are worth trying, I'm partial to the cochinita pibil, which features luscious pork spiked with rusty red achiote, and is accented with creamy black beans and pickled red onion. The habanero salsa served on the side is wickedly spicy, but also mysteriously fruity and complex. $12.