Created by lazyme on February 19, 2015
Step 1: Heat 2 tablespoons oil in heavy large skillet over medium-high heat.
Step 2: Add cabbage, mushrooms, bok choy, carrot and green onions and stir-fry until vegetables are crisp-tender, about 3 minutes.
Step 3: Add 3 tablespoons oyster sauce and 3 tablespoons soy sauce; stir 1 minute to blend flavors. Season to taste with salt and pepper. Transfer vegetable mixture to medium bowl.
Step 4: To same skillet (do not clean) add 1/2 tablespoon oil, remaining 3 tablespoons oyster sauce, remaining 1/2 tablespoon soy sauce, butter and vinegar. Boil until sauce thickens, whisking occasionally, about 3 minutes.
Step 5: Season with salt and pepper.
Step 6: Keep warm.
Step 7: Sprinkle tuna with salt and pepper.
Step 8: Heat remaining 3 tablespoons oil in another large skillet over high heat.
Step 9: Add 3 tuna steaks and cook to desired doneness, about 2 minutes per side for medium-rare. Transfer to small baking sheet. Repeat with remaining tuna.
Step 10: Divide vegetables among 6 plates. Top with tuna. Ladle sauce around tuna.
Step 11: Sprinkle with sesame seeds, if desired.