Place the hock in a saucepan, cover with cold water and bring to a boil. Remove from heat and drain.
In an ovenproof casserole, add 50g of butter and oil and brown the hock on all sides. Add vegetables and sweat for a few minutes, then add the garlic cloves, veal stock, star anise, bouquet garni and pepper (do not salt). Cover the casserole and bake at 130°C/266°F for 3 hours, basting regularly. Alternatively, instead of baking, you can simmer on the stovetop, on low heat for around 2 hours, or until the hock is tender.
When cooked, remove the casserole from the oven and increase the temperature of the oven to 180°C/355°F.
Place the hock in another baking dish, drizzle the remaining melted butter and cook for about 15 minutes to get a nice golden brown.
To make the sauce, strain poaching liquid and add to a large saucepan. Place over medium high until reduced by around two thirds, or until it reaches the desired consistency. Add salt to taste.
