To make the giardiniera, pour the vinegar and 100ml water into a small saucepan. Stir in the sugar and 1 1/2 tsp salt. Bring to a simmer and bubble until the salt and sugar are dissolved. Put the carrots, celery, cauliflower, chilli and garlic in a clean small jar or heatproof bowl, scatter in the peppercorns and fennel seeds, then pour over the hot liquid. Cool fully, then pour over the olive oil. Chill for at least 1 hr, or overnight.

For the olive salad, blitz 75g of the giardiniera, all the olives, the roasted red peppers, capers, garlic and parsley in a food processor until finely chopped but still textured. Scrape into a bowl. Stir in the olive oil, vinegar and 1 tbsp of the giardiniera liquor, then season with black pepper. Chill for 30 mins or overnight.

Slice the loaf in half through the middle. If it has a very thick, fluffy crumb, pull out a little to make room for the filling. Brush the cut sides with the oil, then spoon the olive salad over both halves so the juices soak into the bread.

Layer the mortadella over the base, followed by the salami, then prosciutto. Arrange the provolone over the top. Close the loaf with the top half and press down firmly. Wrap tightly in baking parchment, then set a tray or board on top and weigh it down with a couple of tins. Leave for 1 hr at room temperature before slicing and serving.