Step 1

Place the steak pieces in a 1-gallon resealable plastic bag. Whisk the soy sauce, garlic, ginger, sambal oelek, brown sugar and scallion whites in a liquid measuring cup. Pour the marinade over the steak. Seal the bag, squeezing out as much air as possible. Let marinate for at least 10 minutes and up to 1 hour.

Step 2

Heat 2 tablespoons each olive oil and butter in a large cast-iron skillet over medium-high heat. Remove the steak from the marinade and pat dry. Working in two batches, add the steak to the skillet and cook 3 to 4 minutes per side for medium rare. Remove to a cutting board and let rest while you cook the vegetables.

Step 3

Add the remaining 2 tablespoons olive oil and 1 tablespoon butter to the skillet. Add the green beans and mushrooms and toss to coat. Cook, undisturbed, until the green beans are beginning to brown and blister in spots, 2 to 3 minutes. Toss the vegetables and continue cooking, tossing occasionally, until the green beans are tender and the mushrooms are browned, 5 to 7 more minutes.

Step 4

Slice the steak against the grain. Serve the steak with the vegetables and sprinkle with the sesame seeds and scallion greens.