Preparation Time: 20 minutes + chilling time. Cooking Time: 3 hours 10 minutes.

1. Lay the pork out on a large board and remove a small section (about a fifth) of the skin from the end of the belly pork. Make a cut through the loin section – this increases the area for the herby filling – then rub salt and a few grinds of pepper all over the inside of the meat. Put this to one side whilst the herb filling is prepared.
2. Dry fry the fennel seeds for a few minutes in a frying pan on the simmering plate, hotplate on simmering setting or induction on medium. Allow to cool.
3. Place the thyme, rosemary, garlic cloves, fennel seeds, lemon zest and chilli flakes in a food processor until finely chopped (alternatively chop with a knife or use a mortar and pestle).
4. Spread the herb filling liberally over the pork.
5. Roll the pork up, like a Swiss roll, and tie around the middle, ends and then in-between. Refrigerate for a few hours, or overnight, for the flavours to penetrate the meat.
6. Take the pork out of the refrigerator a couple of hours before cooking so it comes to ambient temperature.
7. Place the sliced onions into the base of the Portmeirion for AGA White Roasting Dish, with the rosemary sprigs and the pork on top.
8. Rub salt into the skin and protect the two ends with a piece of foil, so the exposed meat does not become overbrowned.
9. Place  the roaster in the oven. CAST OVEN: onto the 4th runners down in the roasting oven or oven on R8. FAN OVEN: preheated to R8/210°C/425°C Roast for 45 minutes.
   Reduce the heat. CAST OVEN: transfer to the lowest set of runners in the baking oven or reduce to B4. FAN OVEN: reduce temperature to B4/160°C/325°C. Roast for 25 minutes per 450g, until the juices run clear and meat thermometer reads 68°C.  For a 3kg joint this will be about 2½ hours If the crackling needs crispening up, put it back in the roasting oven or increase heat to R8 for 20 minutes.
10. Remove the pork from the oven and allow it to rest for 15-20 minutes, before slicing. When sliced, garnish with the watercress.
11. Traditionally porchetta is served with the juices from the tin, however if you prefer use the juices to make a gravy.

When purchasing, ask your butcher to remove the bones and score the crackling for you.