Name: Beef and horseradish sauce sandwich
Prep time: 15 min
Cook time: 22 min
Yield: 4
Cuisine: American
Ingredients: For the beef; 1–1.5kg fillet of beef, trimmed and tied; 15g unsalted butter, at room temperature; 1 tsp Dijon mustard; 2 tsp salt; 2 tsp coarsely ground black pepper; For the sandwich; 1 loaf seeded wholemeal bread; Mustard horseradish sauce, recipe follows; 1 bunch rocket; Salt and freshly ground black pepper; Unsalted butter, at room temperature; For the mustard horseradish sauce; 180ml good-quality mayonnaise; 1 tbsp whole-grain mustard; 1 1/2 tbsp Dijon mustard; 1/2 tbsp prepared horseradish; 2 tbsp sour cream; Salt

To cook the beef:
1) Preheat the oven to 240C/Gas 9. Place the beef on a baking tin and pat the outside dry with a paper towel.

2) Mix the unsalted butter and mustard together in a small bowl and spread the mixture over the beef with your hands. Sprinkle evenly with the salt and pepper.

3) Roast the beef in the oven for exactly 22 minutes for rare and 25 minutes for medium-rare.

4) Remove from the oven, cover tightly with aluminium foil and allow it to rest at room temperature for 20 minutes. Remove the strings and slice the fillet thickly.

To make the sandwiches:
1) Cut the bread into 1-cm thick slices. Spread 4 of the slices thickly with the mustard horseradish sauce, top with slices of beef and rocket and sprinkle with salt and pepper.

2) Spread 4 more slices of bread very lightly with butter and place, butter side down, on top of the beef.

For the mustard horseradish sauce:
1) Whisk together the mayonnaise, both mustards, the horseradish, sour cream and a pinch of salt in a small bowl.

2) Serve at room temperature.

Yield: 240ml