Boil the potato for 3 minutes. Drain and set aside.
Heat the oil in pan over low heat. Pan-fry potatoes until golden yellow and set aside. Pan-fry each side of Wagyu beef for about 6 seconds over high heat and set aside.
Stir fry the shallot and red bell pepper until fragrant in the same pan. Add the potatoes, wagyu beef and mixed sauce and stir fry over medium heat. Add the black garlic and mix well.