Slow Cooker Beef Tostadas Recipe

Place the first seven ingredients in a 3- or 4-qt. slow cooker. Cut steak in half and sprinkle with salt and pepper; add to slow cooker. Cook, covered, on low 6-8 hours or until meat is tender. Remove meat; cool slightly. Shred meat with two forks. Return beef to slow cooker and stir in cilantro; heat through. Spritz both sides of tortillas with cooking spray. Place in a single layer on baking sheets; broil 1-2 minutes on each side or until crisp. Spoon beef mixture over tortillas; top with lettuce, tomato, cheese and, if desired, sour cream.