Roast Beef Sandwich

Ingredients

• 227 g (½ lb)thinly sliced roast beef, about 8 slices
• 2wholegrain rolls (or bread slices)
• 4 slicesSwiss cheese
• ½ mediumred onion, thinly sliced
• about 10 g (½ cup)baby rocket
• 1 mediumtomato, sliced
• to tastesalt and pepper
• 60 ml (¼ cup)mayonnaise
• 30 ml (2 tablespoons)prepared horseradish
• 5 ml (1 teaspoon)Dijon mustard
• 5 ml (1 teaspoon)freshly squeezed lemon juice
• to tastesalt and pepper

Instructions

1. 1

   Mix the sauce

   In a bowl, combine the mayonnaise, prepared horseradish, Dijon mustard and lemon juice. Season with salt and pepper to taste, then whisk until smooth and evenly combined.

2. 2

   Layer the fillings

   Arrange the baby rocket on the bottom halves of the rolls, followed by tomato slices. Season the tomatoes lightly with salt and pepper. Add 1 slice of Swiss cheese, 4 slices of roast beef and another slice of Swiss cheese to each sandwich, then top with red onion.

3. 3

   Finish the sandwiches

   Spoon plenty of horseradish sauce over the fillings. Add another tomato slice if you like, then finish with the top half of each roll.

What is a roast beef sandwich?

Roast beef sandwiches are a familiar American deli-style lunch, built around sliced cooked beef in bread with toppings and a condiment. This version pairs the beef with Swiss cheese, vegetables and a creamy horseradish sauce.

The combination works because the beef and cheese are savoury and substantial, while rocket, tomato and onion bring freshness and bite. The tangy sauce pulls those flavours together.

Nutrition and macros by portion

The nutrition label shows one serving as written: 432 calories, 31g protein, 9g carbs, 31g fat.

The roast beef and Swiss cheese provide most of the protein, while the rolls supply most of the carbohydrates. Mayonnaise and cheese contribute much of the fat. Pair a sandwich with a generous salad or extra non-starchy vegetables for a more balanced plate.

Choose the bread and beef

Wholegrain rolls: their hearty flavour stands up to the beef and sauce. If using bread slices instead, choose sturdy slices that can hold the fillings.

Roast beef: thin slices are easier to layer and bite through than thick pieces. Keep the slices loosely arranged rather than pressing them into a dense stack.

Get the sauce balanced

Horseradish: it brings the distinctive sharpness, so whisk it into the mayonnaise gradually if you prefer a gentler sauce. Dijon and lemon add tang to round out the creamy base.

Seasoning: taste the sauce before assembling, since the beef and cheese may already be salty. Add pepper and salt a little at a time.

Layer for a better bite

Vegetables first: placing rocket and tomato on the bottom roll creates a fresh base. Season the tomato lightly as directed so it does not taste flat.

Cheese and beef: the recipe places cheese on both sides of the roast beef. Finish with red onion, then add the sauce and top bun so the fillings stay together.

Keep the textures distinct

Use tomato slices that are firm enough to hold their shape, and slice the onion thinly so its sharpness does not dominate. Assemble shortly before serving to keep the bread from soaking up tomato juice and sauce.

The sauce should be creamy and easy to spread, not watery. Whisk until smooth, then add it in a generous but controlled layer.

Serve it as a meal

The sandwich is ready as soon as it is assembled, making it suited to a quick lunch. Serve with a simple green salad, crunchy vegetable sticks or a bowl of soup.

If packing it for later, keep the sauce separate and assemble just before eating to preserve the bread's texture.

Recipe notes & tips

• Slice the red onion thinly so it is easy to bite through.
• Whisk the sauce until there are no streaks of mustard or mayonnaise.
• Season the tomato lightly rather than adding all the salt at once.
• Arrange the roast beef loosely for a tender, easy-to-eat filling.
• Wait until just before serving to add the sauce if you want the rolls to stay firm.

Variations

• Use sourdough: swap in sturdy sourdough slices for a tangier, toast-friendly sandwich.
• Add pickles: layer in sliced pickles for extra acidity and crunch.
• Make it milder: reduce the horseradish and add more mayonnaise to soften its bite.
• Add leafy greens: use extra rocket for a fresher, greener filling.
• Toast the bread: lightly toast the bread slices before layering for a crisp edge.

Common mistakes to avoid

• Using thick beef slices: they can make the sandwich hard to bite through; use thinly sliced roast beef.
• Adding too much salt: the cheese and beef can already be savoury; season the sauce and tomato sparingly, then taste.
• Overfilling the rolls: too many loose layers can slide out; keep the fillings evenly distributed.
• Assembling too early: tomato and sauce can soften the bread; put the sandwiches together shortly before serving.
• Making the sauce too sharp: excess horseradish can overpower the other flavours; adjust it gradually and taste as you go.

How to store

Store the sauce separately in a covered container in the fridge and use within 3 days. Keep leftover assembled sandwiches wrapped and refrigerated, and eat within 1 day; the bread may soften as it sits. This sandwich is best served cold, so reheating is not needed.

Frequently asked questions