1. Preheat oven to 150 degrees Celsius / 300 degrees Fahrenheit / gas mark 2.
2. Remove the meat from the marinade, pat it dry, and set aside.
3. Strain the liquid into a pot, discard the bay leaf, peppercorns, and cloves and set the vegetables aside for later. Bring the marinade to a boil. There will be some white/grey foam, just skim this off. Set aside.
4. In a large dutch oven, heat the olive oil over high heat. Salt and pepper the meat, then brown well in the pot until it forms a nice crust (around five to eight minutes). Remove from the the pot and set aside.
5. Add the vegetables to the pan and brown them, then add the tomato paste and sugar. Add about a third of the marinade back to the pot and scrape the bottom well. Pour in the rest of the marinade, bring to a boil, then remove from heat.
6. Place the meat in the dutch oven, cover and place in the oven.
7. Cook for about three hours, turning the meat two to three times during cooking.
8. Remove the dutch oven, take out the meat, cover it and let it rest on a cutting board.