Langoustines or prawns with mayonnaise

If it's too late to get your hands on langoustines (Dublin bay prawns), large prawns will go down nearly as well. Good fishmongers will have a bountiful selection of cooked, raw and frozen examples. Always try to buy seawater prawns; farmed freshwater prawns don't taste of very much. The secret with Dublin bay prawns, langoustines and prawns is to serve a good mayonnaise with them. Home-made mayonnaise will keep for a couple of weeks in the fridge. You can make this by hand or in a mixing machine if you're making a large quantity.

Mayonnaise

2 egg yolks (at room temperature)
2tsp white wine vinegar
1tsp English mustard
2tsp Dijon mustard
^1/2 tsp salt
Freshly ground white pepper
100ml olive oil mixed with 200ml vegetable oil
Juice of half a lemon (optional)

Put the egg yolks, vinegar, mustards and salt and pepper into a stainless steel or glass bowl (don't use an aluminium bowl, or it will make the mayonnaise go grey) on a damp cloth to stop it slipping. Mix well with a whisk, then gradually trickle the oils into the bowl, whisking continuously. If the mayonnaise is getting too thick, add a few drops of water and continue whisking the oil. When the oil is all incorporated, taste and re-season if necessary and add a little lemon juice.