2) In a large bowl, toss the onions, tomatillos, jalapenos, and garlic with 1 tablespoon of the oil and spread on a baking sheet.
3) Roast for about 20 to 30 minutes, until soft and starting to brown, stirring twice during roasting.
4) Meanwhile, in a large Dutch oven (or casserole with light fitting lid), add the rest of the oil and heat at medium-high.
5) Brown the pork, in batches, until well-browned. Then return all of the pork to the casserole and cover with chicken stock.
6) Add the roasted vegetables, cover and place in the oven. Cook for about 1 1/2 hours until the pork is very tender.
7) Meanwhile, place the coriander in a food processor with 2 tablespoons of water and puree.
8) Remove the pork from the oven and stir in the coriander puree, then season, to taste, with salt and pepper.
9) Serve with warm flour tortillas.
Cook's Note: If you can't find Tomatillos, try using green tomatoes