1 pound flank steak
1 whole onion
2 ounces guajillo chiles
1 large tomato, peeled
1 clove garlic
1 pound onions, sliced
2 tablespoons oil
1 to 2 chipotle chiles
Dash dried oregano
8 tostada shells
1/2 pound queso fresco, crumbled
Place flank steak, whole onion and salt to taste in large saucepan. Add water to cover. Bring to boil, reduce heat and simmer 30 to 45 minutes or until tender. Remove meat, cool slightly, then shred and set aside.
Place guajillo chiles in small saucepan. Add water to cover and bring to boil. Reduce heat and simmer until tender. Drain chiles, discard seeds and place in blender container. Add tomato and garlic. Puree.
Saute sliced onions in oil. Add chipotle chiles and 2 teaspoons salt. Simmer 10 minutes. Add reserved meat, oregano and guajillo chile mixture. Cook 10 to 15 minutes.
Spoon meat mixture on tostada shells and garnish with queso fresco and sour cream. Makes 8 servings.