You can check and recheck the desayunos board at Taqueria Azteca for migas, which can rightly be considered the breakfast of the gods, but what you'll find is huevos è la Mexicana. Simplicity itself, the dish is practically elemental: eggs, scrambled with tomatoes, onions and peppers. Simple does not mean easy, though, which obviously it is not, because no one else in St. Louis gets it right. And it's not just the eggs, darkened slightly and suffused with smokiness; it's the entire plate. The rice is firm; the beans are soupy, rare this far north, and topped with crumbled queso blanco. (Are they vegetarian? We don't want to know.) There's sometimes avocado, sometimes sour cream, and warm, fragrant corn tortillas. The salsa varies but is generally either a tart, spicy verde or, preferably, a rojo that can sting (the chilequiles rojos can provide reminders of its goodness well into the next day). There's not much in the way of ambiance, and you'll learn to accommodate the rhythms of the service, but what is it you want exactly, anyway? It's not just the best Mexican breakfast in town, it's the best Mexican and the best breakfast.