Braised Beef Pot Pie

Name: Braised Beef Pot Pie
Ingredients: 2 ½ pounds flat iron steak; Kosher salt; Pepper; 2 tablespoons canola oil; ¼ cup unsalted butter; 2 carrots (peeled and cut into 1-inch pieces); 1 red onion (cut into -inch wedges); 1 parsnip (peeled and cut into -inch pieces); 1 celery stalk (cut into -inch pieces); 8 ounces rutabaga (peeled and cut into 1-inch pieces); 8 cremini mushrooms (small halved); 8 garlic cloves; 1 rosemary sprig (6-inch); 2 dried bay leaves; 3 tablespoons tomato paste; 1 ½ cups dry red wine; 1 quart beef stock or low-sodium beef broth; 2 puff pastry sheets (14- to 16-ounce thawed if frozen); 1 egg (large beaten with teaspoon water)