Place the celery, onions, carrots, garlic, bay leaves and thyme springs in a large saucepan or pot and add plenty of black pepper. Put the ham joint on top and pour in enough cold water to cover.
Bring to the boil and boil for 20 minutes, then turn off the heat.
Let it cool down, with the lid off, for a couple of hours. Place in the refrigerator overnight or for a least 6-7 hours.
Pre-heat the oven to 160 °C (350 °F) Gas 4.
Remove and discard the string and the rind from the joint; you will probably be able to do this with your hands now that you’ve soaked it, but use a knife if you need to. Make sure you leave a coating of fat on the top of the meat; don’t strip it right down to the meat.
Put the joint into a roasting pan. Use a knife to score the to pf the fat into diamond shapes. Push some dried juniper berries or pink peppercorns into the gaps in the fat and crack some black pepper over the top.
Cover the roasting pan with foil, place in the preheated oven and bake for 45 minutes.
Remove the foil and increase the oven temperature to 200 °C (400°F) Gas 6.
Return the roasting pan to the oven for 20 minutes, until golden.
This is where a thermometer can be a great help, because the outside of a ham always looks `done’ very quickly but you want to make sure the middle of the ham is at least 80 °C/175 °F on a meat thermometer. Roast for a little longer if it isn’t up to temperature yet.
Remove from the oven, cover with foil again and allow the ham to rest for 10 minutes before carving.
To store any unused ham, wrap it in baking parchment and keep in the refrigerator. Clingfilm/plastic wrap or foil tend to make it a bit soggy. Also, we like to tear a bit off every time we walk by the fridge, so wrapping it in paper makes it easier to access! Eat within 1 week.
There’s no doubt in my mind that roast ham joints on the bone are more succulent, tasty and tender, but suppliers do a fantastic job now of deboning ham joints, which makes them easier for the home cook.