Firstly, grate your butter using a microplane or grater. By doing this you increase the surface area of the butter and allow it to warm up to room temperature quickly so you can mix it without needing to heat or melt it.
2. Add your finely chopped parsley, crushed garlic and some salt and pepper to taste and mix the ingredients with a fork until combined into a dry buttery clump.
3. Using a sharp knife, split your langoustines down the middle and clean, removing the digestive tract that runs along the length of the langoustine. Place onto a pan or plate to dry
4. Heat up your barbeque or grill oven to your hottest heat setting (Approx 250 degrees celsius)
5. Now take small nobs of your butter mixture and dot it all over on top of the meat of each of the langoustine halves.
6. Place onto your barbeque or oven grill meat side facing upwards and grill with the lid closed for 2 minutes.
7. Remove and place onto a plate and serve with wedges of lemon and squeeze some juice onto the meat before serving hot.