Crab Imperial is the classic choice. Crab Imperial is popular in Delaware, Maryland and Philadelphia. The Crab Imperial recipe varies from restaurant to restaurant and some recipe variations are much better than others. Some recipes call for only mayonnaise. Some recipes call for egg yolk and mayonnaise. Some recipes require milk, cream or Béchamel Sauce. When a roux thickened milk sauce is used, the Imperial custard will taste more like Tuna Casserole, which is the wrong flavor profile altogether.
Basically, the best Crab Imperial is made with fresh mayonnaise that is combined with a simple egg custard. This style of Crab Imperial yields a light elegant custard texture that accents the naturally rich flavor of Blue Crab.
I first learned how to make Crab Imperial while cooking in a Philadelphia fine dining restaurant back in the early 1980's. Crab Imperial was an elegant entrée that was also offered as an appetizer portion. Another popular variation was Crab Imperial topped filet of salmon. The Imperial Custard was also adapted to other seafood items. Shrimp and scallops replaced Blue Crab and this combination worked well when baked in an Imperial Custard.
Today's Shrimp and Scallop Imperial recipe is a little bit different than the Blue Crab Imperial recipe that I published a few years ago. As mentioned before, there are many Imperial Custard recipe variations, so if one does not suit the fancy, another one probably will. In recent years, Imperial preparations have such a high proportion of crab or seafood, that they look like ordinary crab cakes or crab dip. Once again, a good Imperal Custard made with any kind of seafood should have an elegant light custard texture. This definition best suits the meaning of "Imperial!"
Mayonnaise is the key ingredient in an Imperial recipe. An Imperial Custard is best when it is made with fresh mayonnaise. Classic French Mayonnaise only requires a few ingredients. A neutral flavor oil is best for making mayonnaise. Olive oil will result in an Italian Aioli flavor, which tastes nothing like real mayonnaise.
Pre-made store bought mayonnaise is not always made with a standard mayonnaise recipe, but some actually are the real thing. Read the label on a jar of mayonnaise. If it says vegetable oil, egg yolk, salt, pepper, vinegar or lemon juice and water, then it is a classic mayonnaise. A light mayonnaise product that has extra water emulsified in the mixture will end up breaking when baked.
This recipe yields about 1 1/3 cups.
Making mayonnaise is simple. The most important part of a mayonnaise recipe is the start. Only a few drops of oil can be added at a time, till the egg yolk and oil starts to emulsify. Only use a neutral flavor vegetable oil. Canola Oil is a good choice. Olive oil has the wrong flavor profile.
The mayonnaise proportion is 1 cup of vegetable oil to 1 egg yolk. The actual volume will be about 1 1/4 cups to 1 1/2 cups, because of aeration.
Many chefs brag about producing 5 gallons or more of mayonnaise from 1 egg yolk, but the physical properties of the mayonnaise will be questionable. A mayonnaise that is made with too much oil will break and separate when baked.
Whisking by hand or using a small cake mixer with a wire whisk attachment is best when making small batches of mayonnaise. A food processor or emersion blender turns at such a high speed that friction heat is produced. When heat is produced when making mayonnaise with a food processor, the mayonnaise will become way too thick too fast and water will have to be added to loosen the texture, so the remaining oil can be added. The result will be a mayonnaise that contains too much water and the durability of the mayonnaise may suffer when baked in a recipe.
The addition of Dijon Mustard at the start of a mayonnaise recipe is a technique that I learned at Le Cordon Bleu. The Dijon Mustard is an emulsifying agent, so it helps when making mayonnaise quickly. The flavor of the Dijon Mustard is not noticeable in the finished product.
Step 1: Place these ingredients in a mixing bowl:
- 1/2 tablespoon of white wine vinegar
- 1 teaspoon of lemon juice
- 2 pinches of sea salt
- 1 pinch of white pepper
- 1 teaspoon of Dijon Mustard
- 1 egg yolk (large egg)
Whisk the ingredients till they are combined.
Step 2: Measure 1/4 cup of vegetable oil. (canola oil is best)
Measure 3/4 cup of vegetable oil.
Step 3: *Use the 1/4 cup of oil for this step.
Slowly add 2 or 3 drops of oil at a time while constantly whisking to start the emulsion.
Only add about 1/2 teaspoon of oil at a time while constantly whisking, till all of the remaining oil in the quarter cup is combined. Wait to add the small increments of oil till each addition emulsifies.
*The emulsion will thicken and ribbons appear on the surface at this point.
Step 4: *Now that the start of the emulsion is stable and thick, combining the remaining oil will be easier to do. The rate of steaming the oil should be like adding 1 tablespoon at a time. Keep in mind that if the oil is added too fast, it will not emulsify and the mixture will break.
Start adding a very thin stream of the oil from the 3/4 cup container while constantly whisking.
Step 5: Continue whisking while slowly steaming the oil, till all of the oil is combined.
Step 6: Check the consistency of the mayonnaise. The finished mayonnaise should be just thick enough for a thin tablespoon to stand straight up when inserted.
*If the mayonnaise way too thick, then add 1/2 teaspoon to 1 teaspoon of warm water while whisking, so the mayonnaise texture is less heavy.
Step 7: Place the mayonnaise in a container.
Chill to 41ºF in a refrigerator. The mayonnaise can be kept chilled for 7 days.
Shrimp and Scallop Imperial:
This recipe yields 1 entrée.
Step 1: Place 1 egg yolk (large egg) in a second mixing bowl.
Add 1/4 cup of cream.
Add 1/3 cup of mayonnaise.
Add 1/2 teaspoon of dijon mustard.
Add 1/2 teaspoon of lemon juice.
Step 2: Add 1 teaspoon of minced shallot.
Add 2 tablespoons of thin sliced green onion.
Add 1 tablespoon of diced pimiento.
Step 3: Add 1 pinch of sea salt and white pepper.
Add 1 pinch of cayenne pepper.
Add 1 pinch of tarragon.
Add 1 teaspoon of chopped Italian Parsley.Gently whisk till blended.
Step 4: Add 10 to 12 medium size shrimp that are peeled and deveined. (Remove the tails.)
Add 3 ounces of small bay scallops.
Stir the ingredients together.
Step 5: Brush a single portion size casserole dish with melted unsalted butter. (A 1 3/4 cup to 2 cup capacity oval casserole dish is good.)
Place the Shrimp and Scallop Imperial mixture in the casserole dish.
Step 6: Place the baking dish on a baking pan.
Place the pan in a 350ºF oven.
Bake till the surface of the Imperial Custard becomes a light golden brown color.
*The custard should gel and the seafood will be fully cooked when the internal temperature is about 165ºF.
Step 7: Remove the pan from the oven.
Place the Shrimp and Scallop Imperial casserole dish on a doily lined serving platter.
Garnish with Italian Parsley sprigs.
Serve with crostini, toast or sliced French bread on the side.
The texture of Shrimp and Scallop Imperial is light, puffy and elegant. The aroma is enticing!