Overview: We find Rick and his daughter, Lanie, at the Mexico City’s colorful Sonora Market, an emporium of medicinal herbs and the best place in town to buy cazuelas, the beautifully rustic earthenware cooking and serving casseroles that define a whole class of stews and taco fillings. We tend to think of taquerías for their familiar grilled and griddled fillings, like carne asada. But, Rick explains, there’s a whole world of stands and shops that have no grill at all and specialize in satisfyingly homey, slow-cooked fillings made in cazuelas with everything from stewed meat to richly flavorful vegetables. Rick and Lanie check out El Güero, a Mexico City institution, popularly known as “Tacos Hola!,” that specializes in slow-cooked taco fillings. Back home in Chicago, Rick and Lanie plan a cazuela-taco dinner. Lanie throws together a quick Pork with Smoky Tomato Sauce and Potatoes in the crockpot before heading off to school. By dinnertime, it’ll be meltingly tender and richly flavored.