Thanks to the beautiful, worthy hounds who suggested Puro Sabor - Peruvian in the Valley. It was shockingly, gorgeously, beautifully good.
Others have claimed it is far better than Mario's. I disagree - I think they're on an even plane, with different excellences.
First of all: bread and aji. Best bread and aji ever. The bread is hot, and has that weird crumbly-dusty crispiness that's sort of fetishized in Chinese pastry baking. It's the best aji-support ever.
Purple corn drink: shocking. Kind of electric, energetic, and about 15 bizarre flavors. Of the purple corn drinks I've had in town (Pollo a la Brasa's, and Natalee's all come to mind as excellent exemplars), this is my favorite - mysterious, dense, and almost chewy with low spice throbbing.
Fried seafood platter: exceedingly good. Puro's batter is denser and more intensely spiced, Mario's is lighter and crisper and more shattering. I think the Puro's batter is a better feat of cooking wizardry, but Mario's got a better touch with the seafood - their calamari comes out with that perfect, edge of melting, tender, just-barely-cooked thing every time. Mario's shrimp and calamari taste a little fresher to me, too.
Plantains: Puro's has the best fried plantains in town. Period. I think I may have had fried plantains at over a hundred places. Puro's win. Somebody buy them a championship belt or something.
Fried yucca: a few pieces came with the fried seafood platter. Very, very well-fried - with that full-oil-permeation-crispiness that some of you double-fried french fry people get all into. For fried cassava, Atlacatl is my favorite for pure cassava flavor, but Puro's gets the Best Frying Technique Honorable Mention.
Saltado - beautiful fries. Excellent saltado. I think I like Mario's saltado a little more - Mario's has this spicing-sauce wizardry, and the saltado gets magically tied together with some soy-and-spice force-lines. Puro Sabor's is more direct - meat, fries, a little sauce, pure. Mario's has more mysterious energetic depth.
I love Puro.
Thank you, Chowhounds.