“Crab casserole” is somewhat generic term for a wide variety of crab dishes that are baked in the oven. Most incorporate crab meat along with both wet and dry ingredients, all of which are poured into a casserole dish. Any type of crab meat can be used, including fish-based imitation crab. During baking, the crab casserole loses its soupy form and becomes a golden baked solid that can easily be sliced into individual portions. Crab casseroles are popular ways to serve crowds, and also do well as a dish to pass at sit-down gatherings.
There are many different ways of making crab casserole, and the only loose parameters relate to baking dish and method. All casseroles, crab included, derive their name from what is known as a casserole dish. This sort of dish is French in origin, and is typically rectangular with deep sides. It is most commonly made of ceramic, porcelain, or glass, and can be covered or not. Casserole dishes that do not come with a cover often need to be tented with foil during baking to promote even heat distribution.
A casserole is not a casserole unless it is baked in the oven. Different recipes call for different heat settings and timing, but baking is a core requirement. Some more modern and minimalist casserole recipes claim to be microwave-ready, but this is neither conventional nor recommended, particularly for large dishes that contain meat or seafood like crab. The steady, uniform heat of an oven is the only way to safely and evenly cook this sort of dish.
Crab casserole was likely first created in seaside communities with rich crab harvests. Baking the meat into a casserole provides an interesting twist on a readily-available staple. There are many different varieties of crab, each with its own distinctive taste and texture. The modern ubiquity of crab meat even far inland means that iterations of this dish can be attempted almost anywhere. Sometimes only frozen or canned crab is available, but this will work.
Any part of the crab can generally be used in baking casseroles. Homemade casserole with fresh-caught crabs usually includes everything but the shell. Purchased crab often comes more divided. Claw meat, legs, backfin, and lump meat are common designations. All will work, though it is common to use meat from but one species or variety of crab in the casserole.
Casseroles usually require some combination of wet and dry ingredients in order to adhere during baking. Bread crumbs, flour, and spices are common dry ingredients. Cheeses, milks, mayonnaise, and dressings often balance these out.
Cooks also generally add other substantial ingredients like vegetables and pasta noodles. All are mixed together in the casserole dish, and are often topped with additional bread crumbs or cheeses. As the dish bakes, the ingredients form a solid with a browned crust that makes and attractive, and usually very tasty, entree.
Crab casserole is almost always served as a hot dish. Most recipes recommend that the meal be given a few moments to rest after coming out of the oven, but otherwise it should be served immediately. Some preparations do tend to improve with time, though. These are often made a day ahead, saved as a covered dish in the refrigerator, then reheated before serving. Reheating in the oven is usually the most efficient way to go, though individual portions can sometimes be warmed over the stove or in the microwave, as well.