What key ingredient gives Quiche Lorraine its creamy texture?

Quiche Lorraine is known for its rich and creamy texture, and this characteristic primarily comes from heavy cream. This ingredient adds a substantial amount of fat, which contributes to the smooth, velvety mouthfeel of the quiche. The heavy cream mixes with eggs to create a custard-like filling, which is essential in achieving the traditional quiche consistency.

While milk can also be used in quiche recipes, it typically does not provide the same level of creaminess as heavy cream does. Sour cream, although it can add a tangy flavor and some richness, does not serve as the primary element that generates the creamy texture. The term "custard" indicates the mixture of eggs and cream or milk used in quiches; however, it is the presence of heavy cream that primarily defines the rich texture of Quiche Lorraine. Thus, heavy cream is the crucial ingredient responsible for achieving that signature luscious quality in the dish.