The regional table / Delaware
Crab Imperial, Bound with a Cooked Sauce Instead of Mayonnaise
Nothing in this dish gets cooked except the sauce, which is the only thing standing between a pound of crab and a puddle.
The earliest printing of the name I can reach comes from neither a cookbook nor a crab house, and not from Delaware. It is an editorial in the Omaha Daily Bee of 24 August 1908, headed Caught With the Goods On, having fun at the expense of Dr. H. W. Wiley, chief chemist of the Department of Agriculture, who had spent years warning the public off rich food — he had found deadly germs in the lobster, placed ice cream under the ban, and put pie in the list of pestilences — and was then discovered in a Washington restaurant on a blisteringly hot evening doing full justice to two imperial crabs, a porterhouse steak with mushrooms, a special salad, and a quart of musty ale. Then comes the sentence that matters here. It should be explained, the Bee tells its Nebraska readers, that the Imperial crab is peculiar to Washington: it is almost as large as a lobster, and one of them is usually looked upon as sufficient to disarrange the digestive powers of a fair-sized dinner party. The writer has plainly never seen one and thinks it is a species. Three years later the same joke went round the country as a syndicated column, and the phrase travelled with it untranslated — two imperial crabs, one large steak and trimmings, a special salad and several mugs of musty ale — in the Yorkville Enquirer of South Carolina on 18 July 1911, the Griffin Daily News and Sun of Georgia on 25 July, and The Citizen of Pennsylvania on 2 August. Not one of them explains the word either.
What that word is doing can be seen better from where it is absent. Jessup Whitehead's The Steward's Handbook and Guide to Party Catering of 1889 is the American caterer's dictionary of the period, and its CRAB entry runs through stuffed crabs, buttered crab, hot crab, crabs à l'américaine, crab pie à la Guernsey and even crab sausages out of Apicius. The stuffed crab is our dish already, forty years before anyone calls it imperial: crabs pulled open, back shells saved whole, all the meat collected and chopped fine, and then a thick sauce made by simmering chopped onion in butter, adding flour, then milk, salt, white and red pepper, yolks, minced parsley, lemon juice, and the crab-meat; shells filled with the mixture; bread crumbs on top; baked. Whitehead uses the word imperial elsewhere — a Sorbet à l'Impérial, a Supreme of Chicken à l'Impérial, an Imperial Pudding, an Imperial Crown for folding a napkin — and never once beside a crab. Charles Ranhofer's The Epicurean of 1894, the Delmonico's book, is the same: Imperial timbales, lamb cutlets Imperial, Imperial salad, a garnishing of artichoke bottoms Imperial, Imperial rice pudding, Imperial punch, and no crab at all. Both of his savoury Imperials, as it happens, are truffles bound with mayonnaise. Maryland's own printed record agrees. Mrs. Charles H. Gibson's Maryland and Virginia Cook Book of 1894 indexes Ratcliffe crab soup, crab soup, crab cakes, boiled crabs, soft crabs, devilled crabs, crab croquettes and crab salad; The Church Cook Book, published in Baltimore by Williams & Wilkins in 1908 and deposited for copyright that November, prints crab soup, deviled crabs and soft shell crabs. Neither book contains the word imperial anywhere. So the dish is older than its name, and the name looks like something written on a menu rather than something a family said at home. Whether Delaware can add anything to that I cannot tell you, and I would rather say so than guess: there is no digitised Delmarva newspaper run in any archive that answers a request, the Library of Congress refuses automated searching outright, the Advantage community newspaper network holds no Delaware or Maryland town at all, and the University of Delaware's digital library would not answer. The two dated recipes I could actually open are post-war, they come from outside the region, and they disagree about the one thing that matters. Lancaster Farming of 24 August 1956 prints Imperial Crab as one pound of backfin crab, a good sized tablespoon of capers plus some juice, salt and pepper, three or four dashes of red pepper and one-half cup of mayonnaise, mixed gently, divided into four individual casseroles, sprinkled with dry bread crumbs, dotted with butter and baked twenty minutes in a 325-degree oven. The Houston Home Journal of Perry, Georgia, on 25 July 1968 prints an Imperial Crab that begins by simmering chopped onion and green pepper in butter and binds its pound of lump with four tablespoons of medium white sauce, Worcestershire, parsley, Tabasco and sherry, stuffed in crab shells or ramekins, sprinkled with Parmesan and baked at 350 degrees for twelve minutes. Mayonnaise against a cooked sauce. The quantities below are worked out for this page on the 1968 side of that argument, which is also Whitehead's side, and the reason why is the whole of the next section.
Why this version works
The salt goes in after the sauce thickens. Meuser tested this directly and her conclusion is blunt: white sauce is curdled when the salt is added before cooking, due to an acid reaction, and the sauce comes out thinner as well, because some of the starch is hydrolysed into a soluble compound. Salted after thickening, she found the same sauce smoother, thicker and better flavoured. It costs nothing to wait, so wait.
A thick sauce, because the crab will thin it. Mary Louise Meuser's 1921 thesis for Kansas State Agricultural College, published in 1922 as Factors Determining the Quality of White Sauce in Large Quantity Cooking, sorts white sauce into four grades by what it is for: thin for soups, medium used in creamed dishes, thick used in scalloped dishes and souffles, very thick for croquettes. Her thick sauce is three tablespoons of fat and three of flour to a cup of milk, and that is what is below. A pound of picked crab sheds a surprising amount of water in fifteen minutes of oven heat, so you start one grade stiffer than you want to finish.
The binder is cooked starch, not a raw emulsion. Mayonnaise is defined by the federal standard of identity at 21 CFR 169.140 as an emulsified semisolid food prepared from vegetable oil and an egg yolk-containing ingredient, and it contains not less than 65 percent by weight of vegetable oil. Two thirds of that jar is oil held in suspension by yolk. Put it in an oven and the yolk proteins set, the thing holding the suspension stops holding it, and the oil comes out and pools. A flour-and-milk sauce fails in the opposite direction: its starch granules have already swollen and burst in the pan, and what they leave behind is a mesh that grips water and does not separate when it gets hot again.
Mayonnaise belongs on top, where breaking is the point. Brushed over the filling it does exactly what it does badly inside — the emulsion splits, oil rises to the surface, and a thin film of oil over a warm protein is the fastest browning you can arrange without a broiler. Half a tablespoon a ramekin colours the top in fifteen minutes. Half a cup stirred through the middle leaves you eating crab in oil.