To make the chalupa shell, sift together the flour, baking powder, and salt. Cut in shortening and add milk. Shape dough into a long cylinder and divide equally into 6 balls. Pat each ball out into a circle 5-inches in diameter (make the circles thinner in the middle so there will be a depression to hold the toppings).
Fry each disc in hot oil until puffed and golden on both sides (turn once). Drain on absorbent paper towels.
Pile your choice of ground beef, tomatoes, lettuce, onions, peppers, and cheese. Accompany, if desired, with salsa, sliced black olives, sour cream, or guacamole.
Makes: 6 very large tacos