Easy Balsamic Glazed Steak Tips and Mushrooms

Ingredients

• 2 tablespoons vegetable oil
• 2 tablespoons unsalted butter
• 1/4 teaspoon freshly ground black pepper
• 1/4 cup tamari or soy sauce
• 1 teaspoon Dijon mustard
• 2 tablespoons balsamic vinegar
• 1 tablespoon granulated sugar
• 1/2 teaspoon kosher salt
• Coarsely chopped fresh parsley leaves, for garnish
• 1 pound cremini mushrooms, halved or quartered if large
• 2 cloves garlic, minced
• 1 1/2 pounds sirloin steak tips, flap meat, or flank steak, cut into 3-inch pieces