Which of the following is a common ingredient for ganache?

Ganache is a classic confection utilized in different ways, including as a glaze, filling, or frosting. The primary ingredients of ganache are chocolate and cream. When heated together, the cream melts the chocolate, creating a smooth and velvety mixture that can be adapted for various uses depending on the ratio of chocolate to cream.

The combination of chocolate and cream not only provides a rich flavor but also an ideal texture, making ganache highly versatile. Adjusting the proportions can yield different consistencies, perfect for a range of pastry applications, from truffles to layered cakes.

Other options do not contribute to the definition or preparation of ganache. For instance, sugar and water are not typical components, while butter may be introduced in variations but is not essential. Eggs and flour are used in baking tasks and would not form the base of a ganache. Thus, chocolate and cream are indeed the quintessential ingredients that define this beloved pastry element.