For one taco you’ll need a corn tortilla, some cooked and seasoned ground beef (we used leftover taco filling), a large egg, salt, and ketchup. Set a small nonstick skillet over medium heat and add a little of the oil. Add the cooked beef and heat it, about 5 minutes. Push the beef to the side of the skillet, add a bit more oil to the center, and break in the egg. Season with salt; fry until the white is set. Heat your tortilla (we do it directly over a gas flame till it’s puffed and a little blistered), and tip the contents of the pan on top. Top with ketchup and enjoy.