Cut roast into large chunks and rub the outside of the pieces with taco seasoning. Heat a small amount of oil in a large saucepan. Add beef and sear each piece on all sides. Place beef in slow cooker and add HERDEZ® Salsa Casera. Cover and cook on LOW for 6-8 hours on HIGH for 4-5 hours or until meat is fork tender. Remove beef from cooking liquid and shred. Serve shredded beef in flour tortillas with condiments such as shredded lettuce, sour cream, HERDEZ® Salsa Casera, and HERDEZ® Jalapeño Peppers (sliced or whole).