Cut sliced beef into 2” (5 cm) width. Grate garlic. Mix the cut beef, soy sauce, 1 Tbsp sake, and starch in a bowl. Let it sit for a few minutes.
Separate the broccoli florets into bite-sized pieces and slicing the stem into thin strips. Put 1/2 cup water in a medium pot and bring it to a boil. Add the broccoli, cover, and cook for 2 minutes. Strain immediately and set aside.
Heat oil in a wok or frying pan, then add the beef and cook over medium heat for a couple of minutes. Next, add the cooked broccoli and stir-fry for a minute. Season with salt, 1 tablespoon of sake, and the grated garlic. Cook for another minute, then plate and serve.
