1. Preheat broiler. 2. In a small bowl, combine mustard, vinegar, olive oil, parsley, and red onion; set aside. 3. Place buns on a large baking sheet. 4. Brush bottom halves of buns with mustard mixture. 5. Arrange roast beef, avocado, and cheese over top of mustard (leave top halves of buns bare). 6. Leave buns open-faced and broil on high for 2 minutes or until sandwiches are warm and cheese is melted. 7. Cover with top halves and serve immediately. ---------------------------------------------------------------------------
Nutrition
Ingredients