Prepare the steaks about 1 hour before cooking. Score the fat of sirloin steaks at 2.5cm intervals. Cut the garlic clove in half; rub both sides of each steak with the garlic, grind lots of black pepper over the steaks and sprinkle on a few drops of oil.
Turn the steaks in the oil and set aside at room temperature.
2. To make the béarnaise sauce, boil the vinegar, wine, shallots and pepper together in a lowsided, heavy-bottomed, stainless steel saucepan until completely reduced and the pan is almost dry but not brown.
Add 1 tablespoon of cold water immediately. Remove the pan from the heat and leave to cool for 1–2 minutes.
Whisk in the egg yolks and add the cubes of butter bit by bit over a very low heat, whisking all the time. As soon as one piece melts, add the next piece; the sauce will gradually thicken.
thicken. If it shows signs of becoming too thick or slightly scrambling, remove from the heat immediately and add a splash of cold water.
Do not leave the pan or stop whisking until the sauce is made. Finally add the tarragon and season to taste.
4. If the sauce is slow to thicken it may be because you are being too cautious and the heat is too low. Increase the heat slightly and continue to whisk until all the butter is added and the sauce is a thick coating consistency.
It is important to remember, however, that if you are making béarnaise sauce in a saucepan directly over the heat, it should be possible to put your hand on the side of the saucepan at any stage.
stage. If the saucepan feels too hot for your hand it is also too hot for the sauce. Heat the grill pan, season the steaks with a little flaky salt and put them onto the hot pan.
The approximate cooking times for each side of the sirloin steaks are: rare – 2 minutes; medium rare – 3 minutes; medium – 4 minutes and well done – 5 minutes.
For fillet steaks: rare – 5 minutes; medium rare – 6 minutes; medium – 7 minutes and well done – 8–9 minutes.
I like to start a sirloin steak on the fat side - cook for 4–5 minutes until the fat renders out and becomes deliciously crisp, then cook on each side to your taste.
Transfer the steak onto a plate and leave to rest for a few minutes in a warm place while you cook the frites.
Deep-fry the potatoes in the oil at 160oC until they are almost soft. Then drain and pop them back in for a minute or two at 180–190oC or until crisp and golden. Drain on kitchen paper and sprinkle with a little salt.
Serve on hot plates with the béarnaise sauce over the steak or in a little bowl on the side and sprinkle over a little chopped tarragon.
Serve with the frites and fresh watercress. Alternatively, thinly slice the steak and serve on a bed of watercress or rocket leaves, drizzle with béarnaise sauce and serve as soon as possible.