To make the Café De Paris, combine all the ingredients and mix together well. Roll into a tight sausage shape with cling film and leave to set in the fridge.
Bring the steak up to room temperature for 30 minutes before you want to cook it (this will help you achieve a more even cook) and pat dry to remove any moisture.
Rub the steak with a little oil and season. Pre heat a cast iron griddle pan in Roccbox and once hot, add the steak to the pan with the sirloin side facing the back of the oven to allow the fat to face the naked flame.
Cook for between 1-2 minutes, flip the steak over and cook for a further 1-2 minutes.
Using tongs, lift the steak up and press the sirloin fat into the hot griddle pan to finish cooking.
Let the steak rest for 8-10 minutes before carving the fillet and the sirloin. Return the steak to the pan and top with two good slices of the butter, turn Roccbox down to it’s lowest setting and pop back into Roccbox to melt the butter for 20 seconds or so.
Serve with your favourite steak accompaniments.