Langoustines au gratin with whipped clementine butter

Procedure

1. Remove the butter from the fridge and keep it at room temperature for one to two hours before whipping it. Once the butter is soft, whip using a mixer with whisk or a hand mixer. Whip for a few minutes until soft and light. 
2. Finely chop the shallots and add to the butter. Use a fine grater and grate the lemon and clementine zest over the butter.
3. Cut the clementine in two and squeeze the juice over the butter. Season with salt and pepper and a small handful of fresh chopped dill. Continue to whip the butter for a further 1-2 minutes. 
4. Find a large oven-proof dish or a deep and long baking tray. Cut the langoustines in two lengthwise with a long, sharp knife. To do so, start by placing the pointy end of the knife at the joint between the tail and the head, where there is a natural “cross”. Turn the knife so that you can first cut the head into two between the eyes. Then turn the knife so you can cut the tail into two lengthwise. 
5. Carefully remove the intestinal tract along the back of the langoustine tail and use a small spoon to remove the unwanted material in the head. If you like, you can rinse the heads and tail. Place the halved langoustines on the dish/tray with the cut side up. Spread a generous amount of the whipped clementine butter on the langoustines.  
6. Heat your oven to the highest temperature or turn on the grill if you have one. Put the dish/tray with the langoustines under the grill for 3-5 minutes. The langoustines are already cooked, so they only have to be heated until the butter has melted and the flesh is warm.