Place the cut chips into a bowl of cold water and rinse well until the water turns cloudy. Leave to sit for a minimum of 20 minutes or maximum 2 hours. Drain into a colander and rinse again under cold water.
Fill a large pot with vegetable or grapeseed oil and bring to 140 degrees Celsius. Using a slotted spoon, carefully place the chips into the hot oil and fry for 4 minutes. Using a slotted spoon, remove the chips from the oil and place back onto the cooling rack. Place the chips into the fridge or freezer until cold.
For the second fry, use the same oil but heat it to 200 degrees Celsius this time. Using a slotted spoon, carefully place the chips into the hot oil and fry for 3 - 4 minutes or until golden and crispy. Using a slotted spoon, remove the chips from the oil and place back onto the cooling rack. Season generously with flakey sea salt and serve.
Steak
Bring the steak to room temperature by taking it out of the fridge at least 1 hour before cooking it. Season well with salt and pepper. Massage the seasoning into the steak and leave to sit for 5 minutes.
On a very high heat, bring a cast iron pan to heat and drizzle with oil. When there is a slight haze coming from the pan, place your steak into it, cooking one steak at a time. Cook for 2 - 2.5 minutes until you get a golden and caramalised crust. Turn the steak over and cook for 2 minutes. After 45 - 60 seconds, toss in the garlic, butter, thyme and rosemary. Allow the butter to melt and baste the steak with the butter while it continues to cook.
Take the steak off the pan and transfer to a cutting board. Leave to rest for 5 - 10 minutes.
Bearnaise
In a small pan on a medium heat, combine the vinegar, lemon juice, shallots and thyme and fry for 4 minutes or until the shallots are cooked and have absorbed the vinegar and lemon juice. Take off the heat and allow to slightly cool. Add to a heatproof bowl along with the two egg yolks.
Melt the butter in the microwave or on the stove top on a low heat.
Bring a small pot of water to the boil. Turn off the heat and place the heatproof bowl with the shallot mixture and egg yolks over the pot. Begin to vigorously whisk until the egg yolks have doubled in size and become pale. Take the bowl off the pot and begin to very slowly drizzle in the butter in ½ - 1 tablespoon amounts. Continue to whisk as the butter is being drizzled in. Continue until all of the butter has been used and you have a thick and creamy sauce. If the sauce needs to be slightly thicker, start to whisk it over the pot of hot water.
Season with a pinch of salt and squeeze of lemon.
Serve immediately with the steak and fries and an extra sprinkling of tarragon.