1. Heat olive oil in a heavy-based pot over low-medium heat, add onion and garlic and saute
until very soft, about 10-15 minutes. Add carrots and jerusalem artichokes, pour over stock
and bring to the boil. Cover with a lid and allow vegetables to gently simmer until partially
cooked, about 10 minutes. Then add fennel, season to taste with salt and pepper and cook
until fennel is tender, about 10 minutes. Remove from heat and adjust seasoning.
2. Take reserved fennel tops and coarsely chop, add 2 tbsp of chopped fennel fronds to
vegetables and stir to combine.
3. For truffled hollandaise, combine vinegar, wine, shallots and peppercorns in a saucepan,
simmer over medium heat and reduce by half, then strain into a heatproof bowl. Add egg
yolks and whisk over a saucepan of gently simmering water until pale and frothy and thick
enough to hold a ribbon when drizzled from the whisk. Remove from heat and gradually
whisk in melted butter, season to taste and stir in finely grated truffle to taste.
4. Ladle braised vegetables into serving bowls and spoon over truffled hollandaise. Shave
over additional truffle and serve.