In a small Dutch oven or a medium, straight-sided pot, heat 2 tablespoons olive oil over medium-high heat. Add a salted-and-peppered pork tenderloin (about 1 1/4 pounds; the standard size) and brown on all sides. (It does not have to cook through.) Once it’s browned, remove from heat and to the same pot, add 1/2 onion (chopped), 1 clove garlic (minced), a dash of red pepper flakes, salt and pepper. Cook until onions are soft, about 3 minutes. Add one 15-ounce can diced tomatoes, 1 tablespoon chili powder, 1 bay leaf, and a few hefty shakes of dried oregano. Stir to combine, then add pork tenderloin back to pot, nestling it in the liquid. Bring to a boil, then cover pot and simmer for about 30 minutes. (If you have to go pick up your spouse at the train because you forgot to tell him you took the car home from the station yourself, well, now is the time to do it.)
While pork simmers away, make a corn salad with cooked kernels, chopped tomatoes, cilantro, scallions, olive oil, a squeeze of lime. Warm 4-6 whole wheat tortillas (wrapped in foil) in a 350°F oven.
When pork has cooked, remove from pot and, using two forks, shred it into pieces as shown above. (There is no art to this; in fact the less artfully done, the better.) Add shreds back to the sauce, stir everything together, then assemble tacos as shown. Top with sour cream.
Jenny Rosenstrach is the author of Dinner: A Love Story and the blog of the same name. She and her husband write The Providers column for Bon Appetit.