4 medium to large ancho chiles
2 tablespoons olive oil
6 ounces lean stew meat, cut into 1/4-inch pieces or smaller
5 cups water
1/2 onion, cut in half
2 teaspoons Mexican oregano
5 cloves garlic
1/4 cup ground cumin
1 1/2 tablespoons olive oil
1 1/2 tablespoons butter
3 tablespoon flour
1/2 cup tomato purée

Preparing the broth*
Toast chiles in an oven preheated to 275 degrees F for 5 to 10 minutes; then stem, de-vein, and seed them. Heat a pot over medium-high heat and add the first 2 tablespoons of olive oil. Just before the oil begins to smoke add the meat. Cook the meat until it has just browned, stirring constantly. Add water, onion and chiles. Cook sauce at a low simmer, covered, for 15 minutes; then remove the chiles, placing them in a blender.

Cover the pot and continue simmering for 1 hour more. When the meat has cooked, remove it and its broth to a bowl. There should be at least 3 cups of broth remaining. If there is more, pour some off; if there is less, add some water.

* You can eliminate this entire step by mixing 1 1/2 cups of Swanson beef broth mixed with 1 1/2 cups water.

Preparing the sauce
Add oregano, garlic and cumin to the blender with the chiles, or mash them in a mortar and pestle. Next, add 1 cup of the broth to the blender and blend for 1 minute to fully incorporate the chiles. Add the remaining 2 cups broth and blend to mix. At this point, strain the sauce or not.

Heat the pot you used over medium heat and add the remaining olive oil and butter. As soon as the butter is melted, add the flour and stir the roux until it just begins to brown and produce a nutty aroma.

When the roux is done, remove the pot from the heat and add about 1/2 cup of the chile mixture, stirring well until it is incorporated with the roux. Replace the pot on the heat and continue adding the chile mixture in small quantities, stirring well after each addition. If you have made your own broth, you may add the reserved meat at this time if you desire. If you ground the cumin, garlic and oregano separately, add them to the sauce at this time. Add the tomato purée. Bring the mixture to a boil and simmer, uncovered, stirring frequently, until the sauce has thickened properly, about 20 minutes.

Yields about 2 cups.