When assembling pieces of pastillage into a final product, which ingredient should be used as glue?

Royal icing is the ideal ingredient to use as glue when assembling pieces of pastillage due to its strong adhesive properties once it dries. This icing, made primarily from egg whites and powdered sugar, dries to a hard, stable finish, allowing for the secure bonding of pastillage components. Its consistency can be adjusted to achieve the desired texture for easy application, making it suitable for both intricate designs and larger structures.

In contrast, while buttercream and whipped cream are excellent for icing or filling cakes and pastries, they are not firm enough to serve as a reliable adhesive. Buttercream, although it can stick to certain surfaces, may eventually soften and lose its grip, especially in warm environments. Whipped cream, being light and airy, does not provide enough stability for pastillage assembly, which requires a firm hold.

Chocolate ganache, while it can provide strong adhesion when it is at the proper temperature, may not be ideal for detailed pastillage construction. It is typically used in decorative work or as a coating rather than as a structural adhesive, as it can remain soft and may not set up firmly enough to hold the delicate pieces of pastillage securely over time.

Therefore, royal icing stands out as the best choice for this application due to its ability to dry