What is a custard?

A custard is defined as a liquid that is thickened by the coagulation of egg proteins, making option B the correct answer. This process typically involves heating a mixture of eggs and milk (or cream) until the proteins in the eggs coagulate and create a smooth, creamy consistency.

Custards can vary in thickness depending on the ratio of eggs to liquid and the method of cooking. For instance, a custard that is baked generally has more body and can hold its shape, while a stirred custard, such as a pastry cream, will be more pourable. This versatility allows custards to be utilized in a wide array of desserts, from sauces to fillings for pastries.

The other options do not accurately describe what a custard is. A type of cake refers to baked goods made primarily with flour, sugar, and eggs, rather than the egg-based thickening characteristic of custards. Pastry dough is the raw mixture used to create pastries and does not involve the coagulation of egg proteins in the same way. Lastly, a type of chocolate is unrelated to the egg-based mixture of custards. Thus, the description of custard as a liquid thickened by egg protein is both precise and encompasses the fundamental qualities of this classic