To make the pickled lemon, heat the vinegar and sugar in a small pan along with 110g water, whisking until dissolved. Allow to cool. Using a mandolin, carefully slice the lemon into 1mm slices, discarding any pips. Place the cooled pickling liquor and lemon into a container. Cover and refrigerate for at least 3 days.
Make the brown bread infusion the day before: Preheat oven to 180°C. Blitz the sourdough in a mini food processor to a fine crumb. Spread out on a tray in a thin, even layer and toast in the oven for 30 minutes, stirring the crumbs and rotating the tray after 15 minutes. Once roasted and dark, remove and set aside to cool completely. Once cooled, place in a bowl with the milk and whisk well. Cover and place in the fridge for 12 hours. Strain the mixture through a fine mesh sieve lined with muslin and squeeze as much liquid from the muslin as possible, discarding the breadcrumbs. Pass the mixture a second time through a clean fine mesh sieve. You will need 175g infusion for this recipe. Cover and store in the fridge until needed.
Prepare the onion shells by preheating a water bath to 88°C. Place 500g water into a pan along with the salt and bring to the boil. Whisk well to dissolve the salt. Remove the pan from the heat and allow the brine to cool completely. Peel and rinse the onions under cold, running water and pat dry with kitchen paper. Place each onion into individual sous-vide bags along with 20g of the brine and seal under full vacuum. Cook the onions for 4-5 hours checking every 30 minutes to ensure they are soft but retain their shape. Remove the bags from the water bath and plunge in a large bowl of ice water and allow to cool completely. Once cooled, remove the onions from the bags and discard any liquid. Pat dry with kitchen paper. Use a sharp knife to make an incision ¼ way down through each onion and place the onions cut side down onto a tray lined with kitchen paper for 10 minutes to drain excess liquid. Drizzle a little olive oil in a pan and place the onions cut side down, colouring the onion over moderate-high heat until dark golden. Remove and set aside to cool. Use a teaspoon to carefully scoop out and discard the middle portion of the onion, leaving a shell made of 4 layers. Set aside in the fridge.
For the royale, place the whipping cream and infused milk into a Thermomix set to speed 4. Bring to 90°C, stopping to check the temperature of the mixture with a probe. Add the two cheeses to the Thermomix and bring the temperature back up to 90°C. Add the remaining ingredients and blitz on full power for 1 minutes, stopping to scrape the sides of the jug. At this time remove the prepared onion shells from the fridge. Once the royale is ready, immediately pour the mixture into the prepared onion shells filled to the top. Return the tray to the fridge to set for 1 hour.
To make the mushroom crumb, preheat a dehydrator to 60°C and tightly wrap the trays with cling film. Heat the oil and butter in a hot pan and add the mushrooms, cooking until partially caramelised. Add the garlic and lemon juice and cook for an additional minute. Remove the pan from the heat. Finely chop and add the parsley, stirring well to mix. Drain the mushroom mixture on a lined with kitchen paper before spreading the mixture out on the dehydrator trays. After 12 hours until dried. Remove and once cooled, blitz in a mini food processor to a fine powder. Cover and set aside to use in finishing the edible soil.
For the rye crumble, preheat the oven to 100°C. Melt the butter in a small saucepan and heat to 180°C. Strain the browned butter and set aside to cool to room temperature. In a small bowl, combine 25g of the butter with malt syrup, rye flour and maltodextrin. Rub the ingredients together using clean fingertips and spread the mixture out on a tray. Bake in the preheated oven for 2 hours. Transfer the crumble to a dehydrator tray lined with parchment paper and place in a preheated dehydrator set at 60°C for 12 hours. Remove and once cooled, blitz in a mini food processor for 5 seconds. Cover and set aside to use in finishing the edible soil.
To finish the edible soil, combine the mushrooms crumb and rye crumble along with the hazelnuts, Japanese breadcrumbs and kombu. Finely chop the chives and mix in. Cover and set aside until needed.
Prepare the artichokes by having a large bowl of water ready. Squeeze the lemon halves into the water, leaving the lemons in the water. Stir in the ascorbic acid. Pull off the tough outer leaves of each artichoke, trimming off the tops and stem, leaving about 3cm from the base of the artichoke. Using a paring knife, peel down the stem around the base of the artichoke and trim any leaves from around the sides. Cut the artichokes into halves then plunge into the acidulated water to prevent oxidation. Heat 500g water in a large pan and add the olive oil, reduced wine, vinegar, salt, thyme, coriander seeds and black peppercorns. Bring to the boil, then remove from the heat and strain through a fine mesh sieve into bowl. Allow to cool. Preheat a water bath to 85°C. Divide the artichoke halves and the cooled barigoule mixture into two sous-vide bags ensuring they are laying flat and in a single layer. Seal under full vacuum. Cook in the water bath for 2-3 hours, until soft but retaining their shape. Remove the bags and plunge in an ice bath. Set aside in the fridge until needed.
To make the Marmite emulsion, melt 25g butter in a pan and gently cook the onions over medium heat until softened. In a separate pan gently heat 75g water with the remaining butter. Once the butter has fully melted, blitz to fully emulsify. Pour the emulsified butter over the sweated onions and transfer the mixture to a tall container, using a hand blender to blitz until smooth. Add the thyme, cover and leave to infuse for 20 minutes. Pass the emulsion through a fine mesh sieve. Stir in the marmite and salt. Set aside to keep warm before serving.
For the baby gem lettuce, bring a large pan of water to the boil. Halve each head lengthways. Remove the yellow, centre leaves and as much of the core as possible by making a v-incision. Blanch the lettuce in the boiling water for 2 minutes, before removing with a slotted spoon and plunging into a prepared iced water bath to refresh. Drain and pat dry using kitchen paper. Cover and set aside until ready to serve.
To prepare the radishes, bring a small pan of water to the boil. Trim the leaves and blanch in the boiling water 45 seconds, before removing with a slotted spoon and plunging into a prepared ice bath to refresh. Drain and pat dry using kitchen paper. Cut into quarters and set aside until ready to serve.
To serve, preheat a steamer oven to 100°C. Place the filled onions onto a deep tray and cover with another tray, acting as a lid. Cook for 8 minutes. In the meantime, heat a little olive oil in a pan. Cook the artichokes cut side down over high heat for 1-2 minutes until golden brown. Remove and drain on a tray lined with kitchen paper. Trim into quarters and season with salt. At the same time, heat a little olive oil in a second pan, cook the lettuce cut side down over high heat until charred, approx. 30 seconds, turning halfway. Remove and drain on a tray lined with kitchen paper and season with salt. Remove the onions from the steamer and sprinkle over the edible soil. Arrange the artichokes, lettuce and radishes alongside. Pour the warm Marmite emulsion around the onion and garnish the dish with freshly chopped chives, pickled lemon and parsley cress.