Griddled Welsh beef fillet steaks with potato and fennel cakes, mushroom and cauliflower ketchup and griddled onions

SERVES 4

4 x 200g Welsh beef fillet steaks 1tbsp rapeseed oil, such as Blodyn Aur, plus a little for the spring onions ½tsp Halen Môn Anglesey Sea Salt ½tsp freshly ground black pepper 4 thyme sprigs 2 bunches thin spring onions or Welsh onions, when available shiitake nushroom powder, for dusting

Put the steaks in a dish with the rapeseed oil, salt, pepper and thyme in a dish, coating them well, and leave to marinate while you prepare the rest of the dish. For the ketchup 100g cauliflower florets, halved 15g dried shiitake mushrooms 1 small onion, finely chopped 2tbsp rapeseed oil, such as Blodyn Aur 1 large garlic clove, finely grated 200g fresh oyster mushrooms, chopped ¼tsp freshly grated nutmeg ¼tsp Halen Môn Pure Sea Salt With Umami No2 4tsp rose balsamic vinegar or white wine vinegar

Cook the cauliflower in salted boiling water for 8 minutes. When soft, pour 100ml of the cooking water over the dried shiitake mushrooms and leave to soften for 12 minutes. Drain the cauliflower and set aside.

Put the onion and rapeseed oil in a wok and cook on a low heat for 12 minutes until soft. Increase the heat, add the oyster mushrooms and stir-fry for 3 minutes. Add the nutmeg, umami salt, vinegar, soaked mushrooms and drained cauliflower. Cook for a further 3 minutes. Tip into a bowl and allow to cool, then blend to a purée in a processor. This will keep for a few days in the fridge. For the potato and fennel cakes 45g salted butter, plus extra for greasing 1tbsp rapeseed oil, such as Blodyn Aur, 3 large banana shallots, halved and thinly sliced across 3 fennel bulbs, trimmed top and bottom and cut in half lengthways, then each piece into 10 wedges 900g Pembrokeshire early potatoes or any creamy potato

Melt 30g of the butter in a pan with the rapeseed oil and add the shallots. Gently fry, stirring often, until soft and golden. Tip into a sieve set over a bowl to catch the buttery juices.

Tip the juices back into the pan, add the fennel and fry until soft and golden. Tip into the sieve with the shallots, catching the juices again to add to the potatoes later.

Preheat the oven to 190C/ 170C F/Gas 5. Liberally grease 4 x 10cmx2.5cm deep tins, base line with baking paper and chill.

Peel the potatoes and thinly slice on a mandoline. Melt the remaining 15g butter with the juices from the drained shallots and fennel. Add to the potatoes, season then layer half the potatoes in the individual tins and add a layer of the shallot and fennel mixture. Top with layers of the remaining potato. Bake for 20-30 minutes until golden and cooked through when pierced with a skewer.

Around 15 minutes before the end of the potato cooking time, remove the steaks from the marinade, reserving the thyme sprigs. Toss the spring onions in a little oil and season. Heat the griddle pan and sear the onions on all sides, adding the thyme sprigs for a second to crisp. Transfer to a warm plate. Wipe out the pan, add the steaks and griddle on a high heat until cooked to your liking (3 minutes on one side and 2-3 minutes on the other side for rare). Transfer to a plate to rest for 8 minutes.

Serve each steak on top of a potato cake with the onions on the side. Top with a dollop of ketchup and a wisp of the crisped thyme, then dust the plate and onions with the mushroom powder.