As amazing as the roast beef dinner is, I think that my favourite part has to be using the leftovers to make roast beef sandwiches! The basic roast beef sandwich is so easy to make and yet so good! I like to start my roast beef sandwiches off with some sweet caramelized onions, which take a bit of time to make but for what they add to the sandwich, they are so worth it! Next up I like to add a bit of bite and I am always torn between using some horseradish or some grainy mustard so I very often just decide to combine the two along with some creamy mayonnaise. Cheese is always a welcome addition to any roast beef sandwich and you can go with some sharp and tangy cheddar or some smooth and creamy swiss or provolone and since melted cheese is always better, you can throw your sandwich under the broiler for a minute or two. No roast beef sandwich would be complete without a hit of tasty gravy, also leftover from the roast beef dinner, and I often like to add something green in the form of peppery arugula. No matter how you do it, you really cannot go wrong with a roast beef sandwich!
Roast Beef Sandwich with Caramelized Onions and Grainy Mustard, Horseradish Mayo
The best part of the roast beef dinner might just be in using the leftovers to make roast beef sandwiches! Tender roast beef with sweet caramelized onions and the bite of a touch of horseradish.
- 1 tablespoon olive oil
- 4 cups onion, sliced
- 1/2 cup water
- 4 buns, cut in half and lightly toasted
- 4 slices cheese, cheddar, swiss or provolone
- 1 pound roast beef, warm and thinly sliced
- 1/4 cup gravy
- 2 tablespoons mayonnaise
- 1 tablespoon horseradish
- 1 tablespoon grainy mustard
- 1 handful arugula (optional)
- Heat the oil in a pan over medium heat.
- Add the onions and water and cook, covered, until completely tender and caramelized and golden, about 40-50 minutes, adding more water as needed.
- Mis the mayo, horseradish and mustard.
- Assemble sandwiches and enjoy!