Broiled Mackerel with butter and green onions

This is a simple way to cook mackerel that yields a delicious result and makes a wonderful first course. Top it with any of the compound butters found in the back of the book. Some favorites are miso butter, mustard-tarragon butter, and ‘nduja butter. This method can also be used for other small fish family members (sardines, anchovies, etc); simply adjust the cooking time for the thickness of the fish. Have your fishmonger clean the fish and remove the backbones without cutting them in hal