Place the ground beef in a small saucepan and sauté over medium heat until browned.
Dice half of the tomato and stir it in along with the mustard; remove from the heat.
Heat and open a package of RAMEN Z, placing the noodles and soup in a serving bowl.
Top with the meat mixture, shredded cheese, lettuce, onion, and pickles (if desired.)
Thinly slice the remaining half of the tomato and arrange it on top as well. Enjoy!