In a sauce pan melt some unsalted butterwith a bay leaf. Add a pinch of nutmeg, a pinch of mace and a pinch of cayanne pepper. Squeeze in the juice from half a lemon and add 1/2 teaspoon of anchovy paste and season with salt and white pepper.
Leave to cool, mixing in the cooked shrimps when the butter starts to solidify.
This can be sealed with a little extra melted butter and will keep for days in the fridge but should be bought to room temp alowing the butter to soften before serving with toast.