1 lemon, juice only
1 tsp Dijon mustard
110g/4oz cornflour
300ml/10fl oz rapeseed oil
sea salt, to taste
110g/4oz self-raising flour
vegetable oil, for deep frying
2 tsp white wine vinegar
2 free-range eggs, yolks only
28 langoustines, shelled and de-viened
275ml/9floz tonic water
2 tbsp vodka