Casa fiesta taco shells take the work out of frying corn tortillas when tacos are on the menu. These ready-to-heat shells are made with corn masa flour, vegetable oil and a bit of lime for natural simplicity. Fill these shells with seasoned ground beef, fajita strips or shredded chicken, and add a topping of lettuce, tomatoes and cheese for a well-balanced meal. Substitute roughly mashed chunks of avocado if you prefer a meatless taco.