Final answer:
The main ingredient in Pastry Cream not found in Crème Anglaise is starch, such as cornstarch or flour, making Pastry Cream thicker and suitable as a pastry filling.
Step-by-step explanation:
The major ingredient that is found in Pasty Cream (often referred to as pastry cream or crème patissiere) and not in Creme Anglaise is starch, typically cornstarch or flour. This starch is crucial in providing the thickened, stable consistency that characterizes pastry cream and differentiates it from the liquid, flowing nature of crème anglaise. While both are custards and share ingredients such as milk, sugar, and egg yolks, the presence of starch in pastry cream allows it to be used as a filling for eclairs, tarts, and other pastries without it running out when cut.