Pat the duck legs dry with some kitchen roll, then sprinkle the duck legs on both sides with the sea salt.
Combine the Shallots, Onion, Garlic, 6 sprigs of Thyme and Parsley in a food processor bowl and pulse until the ingredients are finely chopped.
In a bowl, add half of the mixture and spread across the base. Add the duck and then spread the remainder of the mixture over the duck. Cover with clingfilm, then place in the fridge for 24-36 hours.
When you want to cook the duck, remove from the fridge and wash the curing mixture off the duck before patting it dry. Place to one-side whilst you prepare your BBQ.
You want to set your BBQ up with 2 zones but also need to make sure you keep the temperature fairly low. For the cook I kept the temperature between 120°C and 150°C. The important thing here is not so much the temperature of the BBQ but keeping the duck fat temperature at 100°C.
Once your BBQ is ready to cook on, pour the duck fat into the casserole dish with the Bay Leaves and 4 spring of Thyme. Place onto the indirect side of the BBQ. Do not add a lid to the casserole but place a lid on the BBQ.
Once the duck fat had fully melted, place the duck legs into the fat. They should be fully submerged in the fat. At this stage add the thermometer to the duck fat, so you can monitor the temperature. You want to maintain it at 100°C.
After 2½ hours remove the duck from the duck fat. Place them onto a plate with kitchen roll and pat them dry.
Next, heat a skillet on the BBQ and place the duck legs skin side down until the skin crisps up - 5 to 10 minutes.
Remove the duck legs from the skillet and serve with duck potatoes.