Place the butter in a pan and clarify - melt slowly, allowing the fat to separate from the water and milk solids. Skim off the foam that rises to the top.
Pick the leaves from the tarragon and parsley. Chop the leaves making sure not to bruise the tarragon. Reserve the tarragon stalks.
Peel and finely dice the shallot. Place in a pan with the tarragon stalks, dry white wine and vinegar. Allow to reduce to a fifth of the original volume then remove from the heat and pass through a fine sieve.
In a bowl over a pan of simmering water, whisk the egg yolks with the reduction of wine and vinegar. Whisk until you have a thick sabayon. Remove from the heat and slowly whisk in the melted butter until you achieve a mixture with the consistency of mayonnaise. Whisk in the Chobani yogurt and add the chopped herbs.
Season with salt and pepper and add a squeeze of lemon juice.
Preheat a char-grill until very hot.
Season the steaks with salt and pepper and drizzle with the sunflower oil.
Cook on the char-grill for 3 minutes on each side or until cooked to the required degree.
Wash and spin the rocket leaves in a salad spinner.
Peel and puree the garlic clove with a pinch of salt.
Cut the cherry tomatoes in half, place in a bowl and season with salt. Stir in the crushed garlic, balsamic and olive oil. Leave for 15 minutes for the salt to extract the juices from the tomatoes.
Add the rocket leaves and mix well just before serving.
Serve the steak with a handful of dressed rocket salad and finish with the Bearnaise sauce.
«Allow the steak to rest for a few minutes before serving. This will allow the steak to relax after cooking and will result in a juicier and more tender steak.»