- 4 sirloin steaks, each 200-250g/7-9oz and 1-1.5cm/½-¾in thick, trimmed of all fat and silver skin
- Extra virgin olive oil
- Sea salt and freshly ground black pepper
- 1 beefsteak tomato, about 375g/12oz, cut into 4 even slices
- 4 thin slices red onion
- 50g/2oz triple cream cheese, cut into thin wedges, at room temperature
- Sprigs of flat-leaf parsley, to garnish
- For the dressing
- 4 tbsp sour cream
- 4 tbsp mayonnaise
- 2 tbsp Dijon mustard
- ½ tsp Worcestershire sauce
Place each steak between 2 sheets of clingfilm and pound to an even 5mm/¼in thickness. Lightly brush the paillards with olive oil and season with salt and freshly ground black pepper.
Combine the dressing ingredients in a small bowl, including salt to taste. Lightly brush each tomato slice with oil and season to taste.
Brush the barbecue cooking grates clean. Grill the tomatoes over direct high heat for 2 to 3 minutes until slightly charred on one side. Transfer to a heatproof dish, grilled sides up, and keep warm.
Grill the paillards over direct high heat for 1½ to 2 minutes with the lid open, turning when the first side is nicely marked. The other side will only take 10 to 15 seconds for medium-rare doneness (the paillards will continue to cook as they rest).
Transfer the paillards, with the first grilled sides facing up, to a serving platter or individual plates.
Place a slice of tomato in the centre of each paillard. Evenly divide the dressing over the tomatoes. Separate the slices of onion into rings and place a few onto each tomato. Next, add a piece of the triple cream cheese and a grinding of black pepper. Garnish with a sprig of flat-leaf parsley and serve straight away.