Cut round steak into cubes and brown in shortening in heavy skillet or Dutch oven. Peel and cube potatoes(approximately in 1/2-inch cubes). Once meat is slight browned add potatoes and continue to brown. (Don't worry if it sticks to the bottom of the skillet. Add tomato sauce, salt, pepper, cumin powder and garlic. Add approximately one cup of water and simmer until meat and potatoes are tender. Potatoes will thicken sauce.