1 L fish stockBring all ingredients except butter to the boil in a medium saucepan.
100 g eschallots, finely sliced
5 limes, juiced
500 ml white wine
2 bay leaves
500 g butter, diced
Reduce over medium heat to 200 ml then strain through a fine chinoise.
Gradually add butter over low heat, whisking continuously until completely emulsified.
Season to taste.
Suggestion: Drizzle over saffron-infused crab tarts served with baby asparagus and shizo.