Shrimp or Oyster Curry

Melt four ounces of butter and fry in it four young onions and a clove
of garlic chopped. Add the juice of two limes. Stir into this one
teaspoonful of corn starch, two tablespoonfuls of curry powder and
half a cup of cream with salt, pepper and cayenne. Stir this rapidly
over the fire until very thick. Thin with milk until it is the proper
consistency, then add a large cup of picked shrimps, and as many
oysters. Cook two minutes after it boils.