At the romantic San Angel Inn, a lush hacienda-turned-restaurant in Mexico City's Coyoacan District, Rick enjoys what might just be the most passion-infused food in the Mexican canon: a quintessential plate of perfect chiles rellenos. From there, we visit La Merced - the sprawling, spectacular central market that's the culinary soul of a city with 20 million mouths to feed - where chiles are bought and sold by the thousands. Americans are passionate about chiles rellenos, too. Just ask Rick's customers at Frontera Grill, where only a lucky few who line up on the street get to enjoy them each night before the supply runs out. In the Frontera kitchen, Rick offers a detailed lesson on how they're made - a labor of love that involves many carefully choreographed steps of roasting, filling and sauce prep, stuffing, battering and frying. Then it's time for a crash course in chiles at the National University of Mexico in a visit with Ricardo Munoz-Zurita, a renowned chef and food anthropologist who literally wrote the book on chiles relleno - a popular cookbook devoted to the subject - and runs a cutting-edge restaurant right on campus. The two friends share Ricardo's latest twist on chiles rellenos: an ancho stuffed with plantains. Back at home, Rick explains that chiles rellenos don't have to mean hours of prep time. And to prove it, he shares his recipe for Shrimp Chile Rellenos Grilled in Corn Husks. Next, we're off to Oh Mayahuel, an uber-cool Mexico City restaurant specializing in Mezcal flights and modern Mexican cuisine, to sample their signature stuffed chile: a dried ancho, rehydrated in a tangy escabeche sauce, stuffed with a sizzling steak taco filling and guacamole. If you're passionate about chiles rellenos, this relleno roller coaster ride will leave you feeling thrilled, surprised - and stuffed.