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Two halves of a hot roast beef sandwich up close

Hot Roast Beef Sandwich with Caramelized Onions

Our Hot Roast Beef Sandwich with caramelized onions is the BEST way to use leftover roast beef! Don't just heat up your leftovers - make them into an incredible ciabatta sandwich using remoulade sauce, cream cheese, and sweet caramelized onions.
Course Main Dish
Cuisine American
Keyword hot roast beef sandwich, hot roast beef sandwiches, pot roast sandwich, roast beef sandwich, roast beef sandwich ideas
Prep Time 10 minutes
Total Time 10 minutes
Servings 1
Calories 322kcal
Author Isabel Laessig


  • Knife to halve sandwiches


  • 1 ciabatta roll or sandwich rolls of choice
  • 1 spoonful cream cheese
  • 1 spoonful remoulade sauce
  • 1 spoonful caramelized onions
  • 1 slice tomato optional
  • 3-6 slices roast beef depending on desired serving size


  • Spread 1 spoonful cream cheese on the bottom roll of your sandwich bun.
    Cream cheese spread on a ciabatta roll
  • Add slices of leftover roast beef over cream cheese.
    Roast beef on cream cheese on a ciabatta roll
  • Top with 1 spoonful caramelized onions.
    Caramelized onions over roast beef and cream cheese on a ciabatta roll
  • Add 1 slice tomato (optional).
    Placing a tomato on the hot roast beef sandwich
  • On the top bun, spread 1 spoonful remoulade sauce.
    Spreading remoulade sauce on the top ciabatta roll half
  • Cut in half, serve, and enjoy!
    Completed hot roast beef sandwich



How to Reheat Roast Beef
  1. Add 1 Tbsp. butter to a skillet. Sprinkle in 1 tsp. or so of garlic powder or minced garlic.
  2. Add leftover roast beef and ½ cup of leftover au jus or beef broth. Bring to a slow simmer.
  3. Once simmering, turn off the heat and allow it to heat through. You only want to warm the roast beef, not cook it further.


Calories: 322kcal | Carbohydrates: 29g | Protein: 23g | Fat: 12g | Saturated Fat: 2g | Cholesterol: 53mg | Sodium: 1713mg | Potassium: 320mg | Fiber: 1g | Sugar: 1g | Vitamin A: 375IU | Vitamin C: 43mg | Calcium: 235mg | Iron: 2mg