Roast Beef Sandwich with Caramelized Onions and Grainy Mustard, Horseradish Mayo

Servings: makes 4 servings

Prep Time: 10 minutes
Cook Time: 50 minutes
Total Time: 1 hour

Ingredients

• 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)

Directions

1. Heat the oil in a pan over medium heat.
2. Add the onions and water and cook, covered, until completely tender and caramelized and golden, about 40-50 minutes, adding more water as needed.
3. Mis the mayo, horseradish and mustard.
4. Assemble sandwiches and enjoy!