Crème pâtissière
Crème pâtissière, or pastry cream, is a cornerstone of the dessert kitchen: milk, yolks, sugar and starch or flour, cooked until thick. Unlike anglaise it relies on starch, which is what makes it firm enough to hold its shape.
Starch needs a real boil. The mixture is brought to the boil and cooked for about a minute with constant stirring: only then do the starch granules fully swell, and only then is the amylase enzyme present in the yolk — which would otherwise thin the finished cream — destroyed.
The finished cream is poured out in a thin layer at once, covered with film in contact and chilled fast, so it neither skins over nor sits warm as a growth medium. Before use the chilled cream is whipped or blended smooth: it sets into a solid block as it cools.
Pâtissière is the base for mousseline, diplomat, éclair filling, tart filling and much else.