Preheat oven to 220C/430F.Rinse the pork leg and pat dry with paper towel.Rub the pork leg with the salt, rosemary, granulated garlic and olive oil.Slice the onion and mushrooms into thick slices and line the base of your roasting dish.Sprinkle over the whole garlic cloves and fennel seeds.Place the pork on top of the onion, mushrooms, garlic and fennel seeds.
Place into the oven.Roast for 40 minutes, then turn the oven down to 180C/355F and roast for a further 1 hour and 20 minutes.Remove from the oven and slice to serve.