This steak sandwich recipe includes juicy sirloin steak that has been cut into strips along with red caramelised onions, rocket and a simple dijonnaise sauce. If you’re looking for a recipe that’s quick and tasty then this steak sandwich is for you.

Make this gorgeous steak sandwich to enjoy for lunch or dinner served with some fries or a side salad. You’ll love this sandwich as it is full of flavour and also filling. You’ll find that all the flavours in this sandwich finely complement each other and includes a mixture of savoury and sweet. The sweetness mostly comes from the caramelised onions which really does make this sandwich extra special.
The next time you feel like a delicious gourmet sandwich then give this recipe a try and I’m sure you won’t regret it.
Ingredients for Sirloin Steak Sandwich with Caramelised Onions
For the full list of ingredients and measurements, scroll to the recipe card below.
Sauce Ingredients
- Mayonnaise – I use reduced fat mayonnaise to keep the calories down.
- Dijon mustard – mix with the mayo to make a dijonnaise sauce.
Caramelised Onion Ingredients
- Butter – use unsalted or salted butter.
- Onion – I use a red onion but a brown onion will work too.
- Red wine vinegar - you can use balsamic vinegar instead if you prefer.
- Salt - use fine sea salt for better flavour.
- Sugar – I use soft light brown sugar.
Steak Ingredients
- Steak – I use sirloin steaks. You can use rib eye steak instead if you prefer.
- Salt – I use sea salt but use your preferred cooking salt.
- Black pepper – use good quality black pepper.
- Olive oil – I use extra virgin olive oil.
Additional Ingredients
- Bread – use a baguette which measures around 12 inches and serves 2 or 2 ciabatta rolls
- Rocket – you can use any green salad leaves.

How to Make Sirloin Steak Sandwich with Caramelised Onions
Combine the sauce ingredients
In a small bowl, mix together the mayonnaise and Dijon mustard then cover and refrigerate.
Cook the onions
Melt the butter in a medium frying pan on a low to medium heat. Add in the sliced onions and cook for 2 minutes while stirring. Add the red wine vinegar, salt and sugar and continuously stir the onions for around 10 minutes until soft and caramilsed then remove them from the pan and set aside.
Cook the steak
Season the steak with salt and black pepper then brush with olive oil. Heat a non stick frying pan on a high heat. Add the steak and cook for 2 - 4 minutes. Turn the steak over and cook for another 2 - 4 minutes. Allow to rest for 10 minutes then thinly slice.
Assemble the sandwich
Slice the baguette in half then slice both along the side and open wide. Toast them in the pan with the inside of the breads facing down until golden. Spread the sauce onto the insides of the baguettes then layer with rocket. Add in the sliced steak and caramelised red onions. Serve and enjoy!
Recipe Tips
- This recipe serves 2 but you can easily double the ingredients to serve 4.
Storage
Make this sandwich to serve immediately.
Nutrition
Nutrition based on 1 serving - Calories: 552kcal | Fat: 20.3g | Saturates: 5.1g | Carbs: 55.4g | Sugar: 15.0g | Fibre: 4.6g | Protein: 35.3g | Salt: 2.1g.

Recipes You May Like!
- Steak Salad with Dijon Mustard Dressing
- Beef Broccoli Stir Fry
- Quick Beef Taco Salad
- Deli Style Pastrami Sandwich
Sirloin Steak Sandwich with Caramelised Onions
Ingredients
For the Sauce
- 2 tablespoon mayonnaise (reduced fat)
- 1 tablespoon dijon mustard
For the Caramelised Onions
- 1 tablespoon unsalted butter
- 1 large red onion (or 2 small) sliced
- 2 tablespoon red wine vinegar
- ¼ teaspoon salt
- 1 tablespoon soft light brown sugar
For the Steak
- 1 lean sirloin steak (raw weight around 230g)
- ½ teaspoon salt
- ½ teaspoon black pepper
- 1 tablespoon extra virgin olive oil
To Assemble
- 1 medium baguette (around 12 inches) or 2 ciabatta rolls
- 35g rocket leaves
Instructions
- Prepare the sauce: Make the sauce by mixing together the mayonnaise and Dijon mustard then place the sauce in the fridge.
- Cook the onions: Place a largish frying pan on a low to medium heat and add the butter and allow to melt. Add in the sliced onions and cook for 2 minutes while stirring. Add the red wine vinegar, salt and sugar and continuously stir the onions for around 10 minutes until soft and glazed then remove them from the pan and set aside.
- Prepare and cook the steak: Season the steak with salt and black pepper then brush with the olive oil. Place a non stick frying pan on a high heat and allow the pan to become heat. Once heated, add the steak and cook for 2 - 4 minutes then turn the steak over and cook for another 2 - 4 minutes. Remove the steak, allow to rest for 10 minutes then thinly slice.
- Assemble the sandwich: Cut the baguette in half then slice both along the side and open wide. Place them in the pan with the inside of the breads facing down and toast until golden. Thinly spread the sauce onto both sides of the baguette then layer with rocket. Add in the sliced steak and caramelised red onions. Serve and enjoy!






Leave a Reply