This stew was truly simple and simply divine and that's one reason why I always like Lou Lambert's recipes. Like us, he cooks simply and lets the ingredients shine. Remember the stew is even better the next day. (NOTE: If you live in New Mexico, replace the poblano and Anaheim peppers with roatsed Hatch peppers.)
Place the chunks of pork in a big bowl and season generously with kosher salt and freshly ground black pepper. If using, sprinkle the flour over the pork and toss to coat. Heat a heavy-bottomed Dutch oven or soup pot over high heat and add the olive oil. Add the pork to the pot and sear on all sides to a golden brown. With a slotted spoon, remove the pork chunks and place on a platter.
Lower the heat to medium high and add the onions, cooking until soft, about 3 minutes. Add the garlic and saute another 2 minutes, just don't burn the garlic. Add the Roma tomatoes, cumin, oregano and stir well to combine.
Add the roasted chiles and tomatillos, stock and return the pork to the pan, stir well and bring to a simmer. Cover the pan with a lid and cook slowly for 2 to 2 1/2 hours. While cooking, stir occasionally and add a little more water if needed so the stew is always covered.
When the pork is perfectly cooked for you, add the diced potatoes and masa harina (if using, this will thicken the gravy if you didn't previously flour the pork chunks) and stir well. Allow the stew to simmer another 15-20 minutes until the potatoes are tender. Ladle in bowls. Garnish with fresh chopped cilantro, a dash of Maldon salt, eat, repeat.
To roast chiles, place washed peppers and tomatillos on an aluminum foil-lined baking sheet and place under the broiler on high until they blister and char. Turn and allow to blister and char on the other side. When completely charred--be aware that the tomatillos and jalapeno or serrano will blister quickly--remove from the oven and place in a glass or big bowl and cover with plastic to sweat the skins off. Let sit for 10-15 minutes. Now the blistered pepper skins should come right off. Remove the stem and seeds, rinse lightly, if needed, and roughly chop.