A custard is a sweetened preparation frequently served as a dessert but there are savory versions as well. A basic custard is made with eggs, milk, sugar and milk or cream and a flavoring.
The milk is heated in a pan and brought to a simmer. The eggs, sugar, and flavoring (commonly vanilla) is combined in a separate bowl. The egg mixture is gently whisked into the simmering milk to combine. The mixture is strained then placed either in a single bowl or individual cups. The cups or bowl are placed in a bain marie (water bath) with the water coming half way up the sides of the dish or bowls. The custard should be baked, uncovered until set but still loose, about 35 minutes, depending on the recipe.
The British sometimes use custard powder. The dry mix is combined with milk and cooked on the stove top. This produces a thin custard used more as a sauce.
See other varieties of custard below.
The sweet custard as we know it in the U.S. dates back to the Middle Ages. At that time custard was eaten as we do now as an eggy dessert, or used as a filling in pastries, pies and tarts. Our basic baked custard recipes were brought to America from Europe.
In France they used what Americans call custard as a filling for pastries and tarts and flan which they referred to as "crustade" (a tart with 2 crusts). The term "custard" got it's name from that "crustade". It was sometime in the 16th century that the crustade filling became thicker and used for a dessert served in little individual cups.
Somewhere around the 1840's the European term for custard and the American term for pudding became intertwined. The Europeans brought both recipes for custards and puddings although pudding at that time was a savory mixture of legumes and sometimes meat which was boiled together. Earlier in history American fed their families with similar "pudding" recipes. By the 1840's Americans were well fed and no longer needed that kind of "gruel" to eat.
Enter a gent and Chemist by the name of Alfred Bird. Mr. Bird created an alternative for eggs as a thickener. The product was called custard powder (a powder that contained no eggs just cornstarch,salt, flavoring and a annotto for color). You add the powder to hot milk and it becomes a sweet sauce. American's started using this "egg alternative" and other thickeners such as corn starch for making a custard-like dessert that was more like what Americans call pudding. The An A-Z of Food & Drink, John Ayto added that Mr. Bird created the powder because his wife was allergic to eggs. He marketed the product as a way to make a custard-like dessert which in fact is more like what Americans now call pudding. You can read more about the history of of custard at Foodtimeline.org
There are many other desserts that are types of custards. Here is a list of some that are probably familiar to you. Click on each link to see more information about the dessert.
Creme Brulee - The name translate to "burnt creme. This is a custard topped with sugar then broiled or flamed to create a browned, crisp, crust.
Crema Catalana - A Spanish version of creme brulee. The main difference between creme brulee and crema catalana is that uses corn flour and creme brulee relies on the egg to thicken the custard.
Pots de Creme - A type of custard that includes, eggs, sugar, cream and a flavoring such as chocolate (classic) or vanilla, orange, lime and more. Once baked the cups must be cooled completely, overnight is best.
Creme Caramel - This custard is baked with the caramel on the bottom of the custard (like flan).
Flan - Simple flan uses a similar egg base, sugar, evaporated milk and sometimes other flavorings and even cream cheese. Sugar is caramelized on the bottom of a flan pan then the mixture is placed on top. The flan can be baked in a bain marie (water bath) in the oven OR you can use a double boiler style flan pan and cook the flan on your cooktop. Once the flan has completed cooking and cooled the pan is inverted onto the plate so that the caramelized sugar is on top.
Quiche Lorraine - Even a classic Quiche Lorraine, a savory pie-like dish, is a type of custard.