Wagyu London Broil

1/2 cup Sesame Oil

1/3 cup Sesame Seeds

4 Yellow Onions – sliced

1/2 cup Soy Sauce

1/4 cup Lemon Juice

1 tablespoon Sugar

2 cloves Garlic – crushed

1/2 teaspoon Whole Black Peppercorns

1 (2.5 pound) London Broil Wagyu Steak

Heat sesame oil in a skillet over medium-high heat. Cook and stir sesame seeds in hot oil until golden brown, about 1 minute. Transfer seeds and oil immediately to a large glass or ceramic baking dish. (An alternative method is to let the oil mixture cool and pour into a heavy-duty sealable plastic bag.)
Stir onions, soy sauce, lemon juice, sugar, garlic and peppercorns into sesame mixture until marinade is evenly combined. Place steak into marinade, turning to coat all sides. Cover baking dish with plastic wrap and refrigerate, turning steak often for at least 4 hours or overnight. (Using the alternative method, place ingredients and steak in the plastic bag and remove all of the air before sealing. Refrigerate and flip bag occasionally.)
Preheat an outdoor grill for medium-high heat and lightly oil the grate. (A low broil setting in the oven may also be used.)
Cook the steak on the preheated grill until the meat starts to firm, less than 10 minutes per side. An instant-read thermometer inserted into the center should read 130F. Transfer steak to a plate, cover with aluminum foil and let rest for about 10 minutes. Slice across the grain.

The onions from the marinade may be caramelized in a skillet over low heat and served over the sliced London Broil.