Preheat the oven to 180'C.
Season the steaks with Maldon sea salt. Heat a frying pan until very hot.
Seal the steak on all sides in a hot pan and then transfer to the oven to cook accordingly. Around 8 minutes for medium rare. Rest for the same amount of time as the cooking.
Place the potatoes into cold, salted water. bring to the boil, reduce the heat to a simmer and cook until tender. Drain and keep warm.
Finely slice the mint. Crush the potatoes with the butter using a fork. Fold in the mint and season to taste.
Prepare the asparagus by breaking off the woody base of the stalk. Peel up to the tip and then cook for 3 minutes in salted boiling water. Refresh in iced water.
To serve: Gently reheat with butter.
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.
Carve the beef to show the correct cooking. Place the potatoes into a rectangular mold and lay the beef on top. Drizzle the sauce around and garnish with the asparagus.
«Always rest meat for as long as you cook it. This will ensure even cooking and make it as tender as possible.»
Tender fillet steak with minted and crushed potatoes, seasonal vegetables and a lighter version of a classic French butter sauce.