Remove the steaks from the fridge and allow to come up to room temperature. Place the chargrill on a low heat until you are ready to cook the steaks. Set the deep fat frier to 180 degrees.
Peel the potatoes and place in a bowl of cold water. Using a spiralizer, turn the potatoes so they resemble shoe laces. Soak these these in cold water for at least 30 minutes, otherwise they will not go crispy when fried.
Make sure you butter is at room temperature before you start.
Peel and finely dice the shallot. Peel and grate the garlic. Pick the tarragon leaves from the tough stalks, then finely chop. Roughly chop the tomatoes. Combine all these with the soy sauce and set aside.
Meanwhile, place the soft butter in a food mixer with paddle ( K beater )attachment and whip it, until it becomes light and fluffy. Fold through the reserved tomato and tarragon mix. Season with salt and pepper, if necessary. Set aside until needed.
To cook the steak and chips.
Turn the chargrill to high. Lightly oil the steaks, season with salt and pepper. Place on the grill and cook, turning occasionally until cooked to you desired liking. Whilst the steaks are resting, drain the potatoes and dry, thoroughly, using a J cloth. Cook them in the fryer at 180 degrees until golden and crispy. Drain on kitchen paper and season with salt. Serve immediately.
To serve: Place the steak on the plate, top it with a generous spoonful of butter. Finish with a pile of shoestring fries and some watercress.
«Wrap leftover butter in clingfilm, form into a sausage and freeze. »