Classic Mexican tinga poblana is slow-cooked shredded pork in a sauce of tomatoes and smoky, spicy chipotle chilies. For this one-pan dish, we borrow that flavor profile but instead of braising a tough cut of pork until tender, we start with an already tender cut—a tenderloin—and slice it thinly so it cooks in a matter of minutes. Mexican oregano, which has notes of citrus and earthiness, is sold in most supermarkets. If it’s not shelved with jarred herbs and spice, check the aisle where dried Mexican chilies are sold. If it’s not available, substitute an equal amount of dried marjoram. This is an excellent filling for tacos or topping for tostadas, served with lime wedges, sliced radishes, avocado and crumbled cotija cheese.