Japanese Steakhouse Steak and Vegetables | America's Test Kitchen

Ingredients

• 3 tablespoons unsalted butter , melted
• 2 tablespoons soy sauce
• 2 garlic cloves , minced
• 2 (1-pound) boneless rib-eye steaks 1½ to 1¾ inches thick, trimmed
• 1 1/4 teaspoons white pepper , divided
• 1 teaspoon table salt , divided
• 1 tablespoon vegetable oil
• 2 zucchini (8 ounces each), halved lengthwise and sliced ¾ inch thick
• 2 onions , cut into ¾-inch pieces
• 6 ounces shiitake mushrooms , stemmed and halved if small or quartered if large
• 2 tablespoons mirin