Step 1

Slice the steak as thinly as possible against the grain. Season generously with salt and pepper. Set aside.

Step 2

In a small bowl, stir together the sake (if using), tamari, vinegar, and honey until dissolved.

Step 3

Set a large wok or heavy-bottomed skillet over high heat. Add a thin layer of oil and arrange the steak in an even layer.

Step 4

Brown the meat, flipping once, until there’s a dark sear on both sides, about 3 minutes total. Transfer to a bowl.

Step 5

Add the green beans and sauce to the pan. Simmer vigorously, stirring occasionally, until the sauce has reduced by half and the beans are al dente, about 3 minutes.

Step 6

Return the beef to the pan along with the scallions and toss to coat in the sauce.

Step 7

To serve, arrange the watercress on a platter and top with the beef stir-fry and sauce. Serve immediately alongside white rice, if you like.