8 ancho chiles, seeds and stems removed
1 cup water
2 to 3 pounds pork, cut into 1/2-inch cubes
3 tablespoons vegetable oil
1 large onion, chopped
2 cloves garlic, chopped
2 teaspoons all-purpose flour
2 large tomatoes, peeled and chopped
2 to 3 cups beef stock
1/4 teaspoon dried Mexican oregano
2 tablespoons lemon juice
Salt and pepper, to taste

Cover the chiles with water and simmer for 15 minutes until they are soft. Pur? them in a blender along with the water until smooth.

Brown the pork in the oil. Add onion and garlic and saut?until soft. Add flour and quickly brown, being careful that it does not burn. Add the chile pur? and tomatoes, bring to a boil, reduce the heat, and simmer for 15 minutes.

Add the beef stock and oregano. Cover the pan and simmer until the meat is tender, about 1 1/2 hours. The meat should be tender and the gravy quite soupy. Before serving, stir in the lemon juice.