What addition improves the texture of buttercream icing?

The addition of extra butter improves the texture of buttercream icing by introducing more fat, which contributes to a creamier and smoother consistency. Butter is the primary fat used in buttercream, and when you increase the amount of butter, it enhances the overall richness and mouthfeel of the icing. This extra fat helps to create a silky texture that spreads easily and holds its shape well once applied to cakes or desserts.

By using additional butter, the icing becomes more pliable and can also be whipped to a lighter texture, which can result in a fluffier product. This is particularly beneficial when creating decorations or working with designs that require stability while still being soft enough to easily spread or pipe.

Other additions like milk can also alter the texture but may do so in a way that thins the icing, rather than enriching it. Powdered sugar primarily sweetens the icing and can impact texture but does not inherently create the creaminess associated with butter. Cocoa powder adds flavor and color but does not contribute beneficially to the texture of the buttercream itself like extra butter does.