Warm the oil to around 60 degrees and drop in the curry leaves. Carefully tip this all into a blender and whizz it to aid the infusion of the flavours. Set this aside for 20 mins to infuse.
Pass the oil through a small sieve but don’t worry of a fewbits of curry leaf make it though.
Place the egg yolk, Tabasco finely grated lime zest, lime juice, vinegar and mustard in a small mixing bowl and whisk them together.
Slowly drizzle in the oil a little at a time, whisking all the while.
Continue until all the oil is used up and season well with salt and a little pepper, taste and correct the seasoning if needs be. Store in the fridge for up to a week.