1: The day before cooking, remove about 400g of pine leaves from the branches, then put half of them in a plastic container with a lid. Put the salmon fillets on top and sprinkle with the sea salt flakes. Pour over the olive oil, then add the remaining pine leaves. Put the lid on and give the box a gentle shake. Place the box in the fridge and leave the salmon to marinate for 24 hours.
2: To make the pine nut and parmesan pesto, grind the garlic, thyme and lemon zest together with a pestle and mortar. Add the pine nuts and crush, then mix in the Parmesan. Slowly add the olive oil, season and mix all ingredients together. Set aside at room temperature.
3: Before you plan to cook, light a barbecue and leave the coals to become glowing. Put 1kg of the remaining pine branches on to the coals and then put the grate on top of the branches.
4: Remove the salmon fillets from the marinade and put them straight on to the hot grate. Place the remaining pine leaves on top of the fillets and grill, for 3 minutes.
5: Halfway through the cooking time, brush off the top pine leaves, turn the fillets over and brush with the pine nut and Parmesan pesto and continue grilling for a further 2–3 minutes until the salmon is cooked through and the flesh flakes easily.
6: Remove the fillets from the grate, spread with more pine nut and Parmesan pesto and serve.