This cut of steak is quite expensive, so if you decide to treat yourself you might as well go the whole hog and serve it with some smart trimmings.
Equipment and preparation: for this recipe you will need a blender and deep-fat fryer.
For the dressing, place all the dressing ingredients in a food processor and blend until smooth. Set aside.
For the deep-fried onion rings, whisk the yeast and beer together in a large bowl. Add the flour and whisk to a smooth batter. Set aside for 5 minutes.
Fill a deep-fat fryer or a large, deep, heavy-bottomed pan two-thirds full with vegetable oil. Heat the oil to 180C, or until a breadcrumb sizzles and turns golden-brown when dropped into it. (Caution: Hot oil can be dangerous. Do not leave unattended.)
Dip the onion rings in the batter then lower them carefully into the hot oil (you may need to do this in batches). When the onion rings are golden-brown, remove them from the oil using a slotted spoon and season with salt and pepper. Drain on kitchen roll and keep warm in a low oven until ready to serve.
For the T-bone steak, heat a large frying pan and add the oil. Once hot, add the steak. Cook on each side for 2-3 minutes, depending on how you like your steak cooked. Set aside to rest in a warm place.
For the béarnaise sauce, put the vinegar, white wine, peppercorns and shallot into a small saucepan and bring to the boil. Simmer until the volume of liquid has reduced to about one tablespoon. Strain the liquid into a bowl and then set aside to cool.
Meanwhile, melt 100g/3½oz of the butter in a small saucepan set over a medium heat.
Put the egg yolks in a bowl set over a pan of simmering water and whisk until thickened and light in colour. Gradually add the melted butter, whisking constantly. Season with salt and black pepper. Add the cooled shallot reduction, lemon juice and the chopped tarragon leaves and mix well. Turn off the heat and leave the bowl over the pan until ready to use.
To serve, place the green salad ingredients in a bowl. Add the dressing and toss to coat.
Season the steak with salt and pepper. Cut the steak into slices and place on serving plates alongside the salad and a pile of onion rings. Put the sauce into a jug ready to serve at the table.
