Start with the sauce: Husk and wash your tomatillos then cut in half through the center not through them stem. Using a large baking sheet, Place in broiler on top rack and roast until the skins are mostly black. Remove and let cool.
Stem your peppers and cut in half length-wise. On a separate baking sheet, place the peppers with skin side up and roast in the broiler until the skins are completely charred (approx 8 mins). *Be careful not to roast too long or youll char the flesh under the skin and youll lose your flavor. Remove and let cool long enough for you to handle. Remove the charred skins as much as possible.
Place the tomatillos and peppers into a food processor and process until smooth. Set aside to let flavors meld a bit.
For the meat: Cut the pork into 1 cubes and place in mixing bowl. Add salt, pepper, cumin and ancho and coat the meat.
In a large pan with high sides, add 2 tbs vegetable oil and heat on med-high until shimmering. Add meat and sear on all sides (approx 5-6 mins). Add chopped onion and continue to heat until onions start to get soft and translucent. Then add the garlic and oregano and cook about another 1-2 minutes.
Finally, add in your sauce and the chicken stock, bringing to a quick boil. Reduce heat to low and simmer for 2 hours, stirring occasionally.
To serve, squeeze lime juice in and stir. Then top with chopped cilantro and/or cotija cheese if desired. Enjoy over rice!!
