Truffle butter is a

compound butter Compound butters (french: beurre composé, pl. ''beurres composés'') are mixtures of butter and supplementary ingredients. Primarily, they are used to enhance flavor in various dishes, in a fashion similar to a sauce.Auguste Escoffier (1903), ...

made with

butter Butter is a dairy product made from the fat and protein components of churned cream. It is a semi-solid emulsion at room temperature, consisting of approximately 80% butterfat. It is used at room temperature as a spread, melted as a condimen ...

combined with other ingredients, including

truffle A truffle is the fruiting body of a subterranean ascomycete fungus, predominantly one of the many species of the genus ''Tuber''. In addition to ''Tuber'', many other genera of fungi are classified as truffles including '' Geopora'', '' Pe ...

s or synthetic truffle flavorings such as 2,4-dithiapentane.

References

Spreads (food) Butter {{Food-stub