For the Pithivier

• In large, deep saucepan over a low-medium heat, add the rapeseed oil and slowly cook down the onion slices under a lid until softened but not coloured 20-30 mins, stirring regularly, Season with salt and pepper
• Remove from pan and set to one side to cool
• Potato terrine, preheat the oven to 150C. Grease a 400x 300 x 100mm oven proof baking dish, casserole or roasting tin and line it with baking parchment
• In a large bowl mix the potato slices with the confit onion, picked thyme, melted butter and crushed garlic
• Arrange the thin slices of potato in overlapping layers in your baking dish, seasoning each layer with salt and pepper as you go, until it is around 8cm deep
• Top with another piece of baking parchment and put a heavy tray on top to weigh it down. Cook at 150C for 1.5 hours (check after 40 minutes) or until it’s fully cooked and you feel no resistance when you insert a skewer or pointed knife
• Allow to cool with the weight still on
• When cool, add an additional weight and move to the fridge for at least 4 hours or ideally overnight
• Use a 7cm cooking ring to cut out 4 rounds of potato terrine. Use a sharp knife to cut each round in half horizontally, so you have 8 discs in total
• Blanch the spinach in boiling salted water for 2mins.
• Drain and plunge immediately into iced water, once cold
• Drain and lay out the blanched leaves on a clean tea towel

Assembling the Pithivier

• Place double layer of cling film onto the work surface, brush with a little rapeseed oil
• Arrange a layer of spinach, followed by one disc of potato, then a generous shaving of truffle, some finely grated Cômté cheese and some more spinach
• Wrap in the cling film tightly to create a firm cylinder and chill in the fridge for 30 minutes
• Roll out your puff pastry and cut out two 9cm circles
• Brush beaten egg on one circle to be the bottom of the pithivier
• Remove the cling film from the potato cylinder and place on top
• Lift the second circle of puff pastry to cover the cylinder, press down the edges to seal then return to the fridge to firm up for 15 minutes
• Repeat until you have four pithiviers in the fridge
• Egg wash the top of the pithivier generously,
• Score with the back of a knife, being careful not to cut through the pastry (the classic design is curved lines from the middle of the top disc and down to the edge, as pictured)
• Place into the fridge until ready to cook
• Place the finished pithiviers onto a flat baking tray, lined with greaseproof paper, into a preheated oven at 190C for 25 minutes until golden brown

For the Salsify

• Add the lemon juice to enough water to submerge the salsify in
• Wash, top and tail, peel the salsify, place immediately into lemon water to maintain white colour
• Drop the peeled salsify into boiling salted water for 4 mins
• Drain and refresh in ice cold water
• Drain well and cut into 5cm lengths, Heat a large frying pan, and Sauté in a little oil and butter, with crushed garlic and thyme. Season to taste.

For the truffle beurre blanc

• In a thick bottomed sauce pan, pour the white wine, bring to the boil and simmer until you have half the amount
• Add double cream and bring up to boil
• Whisk in fridge-cold diced butter until thick and emulsified (do not reboil)
• Season with lemon, salt and finely chopped truffle shavings
• In a thick bottomed sauce pan, pour the white wine, bring to the boil and simmer until you have half the amount
• Add double cream and bring up to boil
• Whisk in fridge-cold diced butter until thick and emulsified (do not reboil)
• Season with lemon, salt and finely chopped truffle shavings

For the mushrooms

• Clean and trim wild mushrooms- removing any mud or leaves, if particularly dirty you can rinse in cold water and leave to dry on a paper towel (but where possible try to use a little brush, or scrape down with a knife)
• Heat a large frying pan and sauté in oil and butter, add half a bashed clove of garlic and thyme and season generously
• Remove thyme and garlic, add chopped tarragon