French Dip Sirloin Sandwich

A full sirloin per sandwich - that's where this starts. You slice it thin, finish it in a soy-and-onion broth so it drinks up all that flavour before it hits the bread, then you dip the whole thing. The au jus isn't a garnish, it's the point of the dish. Mustard-mayo, melted cheese, peppers, part-baked baguette. Thirty minutes and it's one of the best sandwiches you can make.

Onion broth (au jus) - ingredients

• 1 large onion, sliced
• Butter
• 2 cloves garlic — or equivalent paste
• Small pinch of sugar
• Splash of rice wine vinegar
• ~2 cups water
• ~1 tbsp soy sauce — adjust to taste
• Black pepper

Steak - ingredients

• 2 sirloin steaks — 1 per sandwich
• Salt
• Black pepper — use twice as much as the salt
• Oil or butter, for the pan

Sandwich - ingredients

• 2 part-baked baguettes — or 1 large baguette split
• Cheese — melted on the top half
• 1 part mustard + 2 parts mayo — mix together
• Red or yellow peppers, sliced

Method

Onion broth

1. Cook the sliced onion in butter over medium-high heat. Add the garlic, a pinch of sugar, and a splash of rice wine vinegar. Cook until soft, slightly browned, and fragrant.

2. Add ~2 cups of water and scrape the pan to lift anything stuck to the bottom. Add the soy sauce and a few cracks of black pepper.

3. Simmer on medium-low for 10–15 minutes. Taste and adjust - more soy for depth, a knob of butter if it needs richness. Leave the onions in the broth.

Steak

1. Pat both steaks dry. Season generously with salt and black pepper - use roughly twice as much pepper as salt. This crust is what the sandwich is built on.

2. Heat a pan with oil or butter to medium-high/high. Cook each steak: 2 minutes on the first side, 2 minutes 30 seconds on the second.

3. Rest for 5 minutes. Then slice thin, against the grain.

4. Add the sliced steak to the hot broth for 1–2 minutes, checking as you go - you want it to absorb flavour and finish cooking gently without going tough.

Assembly

1. Melt cheese on the top half of each baguette under the grill.

2. Spread the mustard-mayo mix on the bottom half.

3. Layer on the sliced peppers, then pile on the steak and onions, lifted together from the broth.

4. Close the sandwich. Pour the remaining broth into a bowl and serve alongside for dipping.