Making the sauce:
Pour a tablespoon of white wine vinegar into a small saucepan, along with one roughly chopped shallot. Heat on high for 5 minutes and then remove from heat.
In a large bowl, whisk 4 egg yolks and a splash of water until pale. Sieve the vinegar mixture into the egg mixture, removing all shallots.
Boil a pan of water and place the large bowl with the egg and vinegar mixture on top. Continually beat the mixture until it begins to thicken.
When the sauce feels thick and peaks at the tip of the whisk, remove from the heat.
Melt 200g salted butter in a pan and slowly whisk into the egg mixture until fully combined.
Now chop your herbs and add to the sauce, along with the juice of one lime. Fold everything together and season with salt and pepper. Set sauce aside as you cook your steak.
Cooking the steak:
Remove steaks from the fridge at least 30 minutes before cooking and pat dry with a paper towel to remove any excess moisture. That way, your dry steak will crisp up nicely on the outside.
Heat a heavy based pan or griddle on a high heat. Season your steak with salt and freshly ground black pepper and then place the steak into the piping hot pan and cook for 4 minutes on the first side.
Now turn your steak and add the 30g of butter, 1 crushed garlic clove and sprig of thyme. Baste with the melted butter mixture and continue to cook for a remaining 1 minute.
Remove the steak from the heat and set aside to cool for approximately 7-10 minutes.
Serve your steak by slicing it against the grain and pouring your chimichurri béarnaise all over.