Make a savoury pastry in the Thermomix, rest for 1 hour, line tartlet moulds and blind bake in the oven. For the duxelle tart filling, sauté the shallot, chestnut mushrooms and a few of the wild mushrooms in a little butter very quickly and season. Place in TM bowl with parsley and thyme. Pulse until a purée, finish with a little truffle oil and 4 chopped wild garlic leaves. Set aside.
For the rarebit , heat the beer and cheeses 3 minutes/90°C/Speed 4. Add the eggs, flour, breadcrumbs and seasonings and cook 5 minutes/90°C/Speed 4, place in a container and cool. Tip – if it splits, add a little whipping cream and beat at Speed 5 until re-emulsified.
For the celeriac purée, add celeriac, cream, salt and white pepper and cook 20 minutes/90°C/Speed 5. When cooked, blend 1 minute/Speed 10 until a smooth purée, set aside to keep hot.
Sear and roast the fillet in a hot oven for 4 to 5 minutes until rare, leave to rest.
For the wild garlic froth, place the chicken stock in a saucepan and reduce by half, add the cream, bring to the boil, tip into the TM bowl with the wild garlic. Blend 1 minute/Speed 10.
Just before serving, place the mushroom mix in the tartlets with a little of the rarebit on top of each. Bake in a hot oven until golden brown.
To serve, carve the fillet and serve on the plate with the celeriac, the tartlet, and the remaining wild mushrooms sautéed in a little butter and seasoned. Sprinkle the wild mushrooms with some chopped wild garlic and scatter them on the plate. Finish the dish with some of the warmed jus, wild garlic froth and a few fresh truffle shavings.