Step 1

Start with the braised kombu. Place the dried seaweed in a small pan and leave to soak for 1 hour, or until soft and pliable

Step 2

Once the kombu has finished soaking, place the pan on a very low heat and cover with cling film. Cook gently for 2–3 hours with the seaweed completely covered – topping up the water if necessary – ensuring the liquid doesn’t come up to the boil. Reserve in the pan of liquid until ready to serve

Step 3

Meanwhile, prepare the pickled onions by placing the vinegar, wine and sugar in a pan and bringing the mixture to the boil. Add the red onion quarters and immediately remove the pan from the heat. Cover with cling film and leave to cool until ready to serve

Step 4

For the alexander purée, bring a pan of water to the boil over a medium heat and add the potato slices. Cook for 5–10 minutes until just cooked through

Step 5

While the potatoes are cooking, add a drizzle of sunflower oil to a pan and place over a medium heat. Add the sliced shallots and a pinch of salt and sweat down for a few minutes until softened

Step 6

Add the stock to the pan and bring to the boil. Stir in the alexander leaves and parsley and cook for 30 seconds, then remove from the heat and transfer to a blender along with the potato slices. Blitz together to form a smooth, loose purée, adjusting the seasoning if required

Step 7

Pass the purée through a fine sieve to ensure it is completely smooth, transferring to a clean pan. Place over a very low heat and keep warm until ready to serve

Step 8

Preheat the oven to 140°C/gas mark 1

Step 9

Place the trimmed fat from the beef in a ovenproof frying pan over a low heat. Heat until the fat begins to render down and coat the pan, removing any remaining solid pieces. Increase the heat of the pan and sear the beef on all sides until dark and golden-brown then transfer to the oven. Cook for 10–15 minutes until medium-rare, with a core temperature of 50°C

Step 10

Remove the sheets of braised kombu from their cooking water and cut into small squares. Return to the pan and warm through gently over a low heat. Meanwhile, drain the red onion from their pickling liquor and cut into thin slices

Step 11

Once the beef has cooked, remove from the pan and set aside to rest for 5 minutes. Place the roasting pan back on the heat and add the alexander shoots to fry in the residual fat for a few minutes until caramelised and golden

Step 12

To serve, carve the rested beef into 1cm slices and arrange on warmed serving plates with a spoonful of purée, the caramelised shoots and slices of red onion. Drain the squares of kombu and scatter over the plate before garnishing with the carrot and parsnip slices