Sesame Stir-Fried Pork with Shiitakes

Ingredients

• pound pork tenderloin, trimmed of silver skin
• well-drained napa cabbage kimchi, roughly chopped, plus 2 tablespoons kimchi jui
• tablespoons soy sauce, divided
• Kosher salt and ground black pepper
• tablespoons grapeseed or other neutral oil, divided
• ounces fresh shiitake mushrooms, stems discarded, caps sliced ¼ inch thick
• medium large garlic cloves, thinly sliced
• tablespoons mirin
• tablespoon toasted sesame oil
• tablespoons sesame seeds, toasted
• bunch scallions, thinly sliced