PREPARING THE MARINADE
In small bowl, add the sugar, minced garlic, kosher salt, freshly ground black pepper, fish sauce, and grapeseed oil. Place your Fullblood Wagyu beef pieces in the bowl, and coat them in the marinade.Cover the bowl with plastic wrap, and let the bowl sit in a cool spot in your kitchen for 2 hours.

PREPARING THE SAUCE
In a separate small bowl, mix together the rice wine vinegar, mirin, soy sauce, fish sauce, and white sugar. This is your sauce.

PREPARING THE SHAKING WAGYU BEEF
Heat a large wok on high heat, and add in 2 tablespoons of grapeseed oil. Once the oil is slightly smoking, add in half of the marinated Fullblood Wagyu beef in a single layer in the pan. Leave the beef undisturbed in the wok for 60 seconds until a brown crust forms. Then, turn the beef and brown the other side. NOTE: Browning the beef will take 3 minutes. Add half of the sauce into the wok, and shake the pan to release the beef.

Add in half of the red onions, and cook for 30 seconds longer. Add 1 1/2 tablespoons of butter to the wok, and stir until melted. Remove the ingredients from the pan, and place them in a bowl. Repeat the process with the remaining ingredients (2 tablespoons of grapeseed oil, the other half of the marinated beef, the other half of the red onions, and 1 1/2 tablespoons of butter).When cooking the second batch, add in the scallions when you add the butter to the wok.

Once the second batch is done cooking, place the ingredients in the bowl with the first batch.

FINAL STEPS
Divide the watercress between 3 to 4 plates.Divide the shaking Wagyu beef between the plates (placing it on top of the watercress).Serve the dish with a few lime wedges, and enjoy!