Heat the broiler. Lay the whole tomatillos and serranos on a broiler pan or baking sheet. Set the pan 4 inches below the broiler and let roast until the tomatillos are softened and splotchy black in places (the skins will split), about 5 minutes; your goal is to cook the tomatillos through while they roast, which means they'll change from light bright green to olive green on the top side. With a pair of tongs, flip over the tomatillos and chiles and roast the other side for another 4 to 5 minutes or so. Set aside to cool. Turn the oven down to 425 degrees. Separate the onion into rings and, on a similar pan or baking sheet, combine them with the garlic. Place in the oven. Stir carefully every couple of minutes, until the onions are beautifully browned. (They're going to look wilted and translucent, even have a touch of char on some of the edges.) The garlic should feel soft and be browned in spots. The total roasting time will be about 15 minutes. Cool to room temperature. In a food processor, place the onion-garlic mixture and the serranos, and pulse until moderateley finely chopped, scraping everything down with a spatula as needed to keep it all moving. Scoop the mixture into a large bowl. Without washing the processor, coarsely puree the tomatillos with their juice, no need to peel off their darkened skin or cut out their cores. Stir them into the chiles. Stir in enough water to give the salsa an easily spoonable consistency. Stir in the cilantro. Taste and season highly with salt. Taste again and, if you like, add just enough sugar to take the edge off the bright tanginess of the tomatillos. If you are planning to use your salsa right away, simply pour it into a bowl and it is ready, or refrigerate it covered and use within 5 days.;
FOR THE PORK:
In a medium saucepan, combine the beans with 3 cups of water and the herbs and bay leaves. Partially cover the pan and bring to a good rolling boil over high heat. Reduce the heat to medium low and simmer the beans very gently (still partially covered) until they are tender, about 1 hour (if you simmer them gently enough, they won't begin to fall apart before becoming thoroughly tender). Add more water if the beans ever begin peeking up above the surface of the water. While beans cook, in a 6 quart Dutch oven cook the bacon slices over medium heat, turning them occasionally, until thoroughly crispy. Remove to drain on paper towels, and when cool, crumble. Tip the Dutch oven slightly, spoon off most of the fat that collects, and add it to the simmering beans. Heat the oven to 325 degrees. If your pork loin roast is in 2 sections that have been tied together, untie them. Sprinkle the meat liberally with salt. Heat the Dutch oven over medium-high until quite hot. Lay in the pork and brown thoroughly on all sides, about 10 minutes total. Pour in the salsa and nestle in the epazote if you it. Cover the pot and place it the oven. Cook until the pork registers about 150 degrees on a meat or instant-read thermometer; the meat will feel rather firm (not hard) to the touch, and cutting into the center will reveal only the slightest hint of pink. The total cooking time should be about 45 minutes. Remove the epazote and set the pot aside uncovered. When the beans are tender, season them with about 1 teaspoon salt, let stand for a few minutes for the beans to absorb the seasoning, then drain off their cooking liquid. Remove the pork to a cutting board, add the beans to the pork pot, set over medium heat and season with salt. Slice the pork, laying the slices slightly overlapping on a warm serving platter. Spoon the beans and sauce around the meat, sprinkle everything with the crumbled bacon, garnish with herb sprigs and carry to the table.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.
Recipe courtesy of Rick Bayless, "Salsas That Cook"