Black garlic and porcini porchetta with truffle Manchego mash

Place pork on a wire rack over an oven tray and refrigerate uncovered for at least 24 hours or up to 3 days.

For black garlic-porcini paste, drain mushrooms (reserve soaking water for jus). Squeeze excess water from mushrooms, then transfer to a food processor with remaining ingredients, 2 tsp salt flakes and 1 tsp coarsely ground black peppercorns and process to a smooth paste.

Preheat oven to 230°C fan-forced. Place pork belly skin-side-up on a chopping board. Using a sharp knife, remove one third of the pork skin from one of the short sides, then invert pork flesh-side up. Score flesh in a criss-cross pattern about 1cm-deep, then rub paste into cuts. Starting with the skinless side of the belly, roll to form a cylinder and tie at 2cm intervals with kitchen string (see note).

Place pork on a wire rack set over an oven tray. Brush skin with white wine vinegar, then scatter with 50gm fine salt to form a crust. Transfer to oven and roast until crackling forms all over (30-40 minutes). Remove pork from oven. Reduce oven temperature to 130°C fan-forced. Carefully, brush off salt crust from pork skin and discard. Place onions in the base of a roasting pan and place pork on top. Return to oven and roast until pork is very tender (3 hours; see note). Transfer pork to a
baking tray, cover loosely with aluminium foil and set aside to rest (30 minutes).

For pan jus, drain excess fat from pan, then place over high heat. Deglaze with Madeira and wine, scraping the base of pan to remove caramelised bits and separate onions, then simmer until reduced slightly (5 minutes). Stir in broth, vinegar,
porcini soaking liquid and any resting juices, bring to the boil, then reduce heat to medium-high and simmer until reduced to a jus (20-25 minutes). Strain into a small saucepan, pressing down on solids to extract maxiumum flavour, then stir in rosemary, lemon zest and juice and lightly season to taste. Set aside.

Meanwhile, for truffle Manchego mash, place potatoes in a large saucepan of cold salted water and bring to the boil over high heat. Cook until potatoes are tender when pierced with a sharp knife (12-15 minutes). Drain, cover with a tea towel and stand to steam dry (2 minutes). Pass through a mouli or potato ricer in batches into a large saucepan. Meanwhile, heat mascarpone and milk in a small saucepan over low heat until warm. Stir potato over low heat until smooth, then add mascarpone mixture and Manchego, in batches, beating with a wooden spoon until mash is smooth and fluffy, then season to taste. Keep warm.

Warm jus over low heat. Transfer porchetta to a chopping board and thickly slice with a serrated knife. Divide truffle mash, porchetta slices, sautéed broccolini and cavalo nero among warm plates. Spoon over jus and scatter with fresh sliced truffle and
extra finely grated truffle Manchego to serve.