4 plump ears of corn
5 Ancho chilies, — stems removed, seeded
2 teaspoons ground cumin
1 teaspoon ground coriander
1 teaspoon ground Mexican oregano
2 tablespoons corn oil
1 large onion, finely diced
4 garlic clove minced
1 12-ounce bottle Mexican beer
3/4 cup chicken stock
Salt Lime juice
Cut kernels from corn cobs and set aside; you should have 2 cups of whole kernels. With the back of a knife, scrape down cobs to remove liquid and pulp. Reserve in a small bowl; you should have a 1/2 cup of corn puree.
Soak chilies in hot water to cover until soft. Drain, reserving soaking liquid. In a blender combine chilies, cumin, coriander, oregano and tortillas. Blend, adding just enough reserved
chile liquid to make a thick paste. Heat oil in a saucepan over medium-high heat. Pour in chile paste and fry for about 3 minutes, or until it thickens. Add onion, garlic and corn kernels and fry
2 minutes more. Add corn puree, beer and chicken stock. Bring to a boil, and simmer for 40 minutes, or until mixture is thick and flavorful. Season to taste with salt and lime juice