If frozen, allow the shrimps to defrost, then blot dry on absorbent kitchen tissue. Place about two-thirds of the butter into a small pan and add all the spices and salt to taste. Add the shrimps and heat very gently for a few minutes (do not allow the butter to brown). Divide the mixture between four cocotte or ramekin dishes (small glazed dishes usually about 3½" in diameter by 1½" deep) and pack the prawns down tightly. Chill until set.
Heat the remaining butter until it has just melted, then pour it evenly over the shrimp mixture so that it forms an airtight seal. Cover and keep in the refrigerator for at least a day to help develop the flavour. Garnish each dish with a slice or twist of lemon and serve with hot whole-wheat toast.