Encore Mondays, April 25 - May 30, 2022 at 10 p.m. on KPBS TV / On Demand. This week Chef Marcus Samuelsson visits Chicago’s longstanding Mexican community — the second largest in the U.S. — to learn about its heritage and cuisine. He tastes tacos de cecina and grilled nopales, and learns the secrets of mole sauce from a master.