After the development of Lakoff’s Theory of Conceptual Metaphor, metaphor and metonymy are understood as fundamental tools. These give an account of the semantic motivation for idiomatic expressions. In this regard, this research project examines the cognitive motivation of certain English food idioms, like ‘be a cup of tea’, ‘bread and butter’, or ‘walking on eggshells’, as well as some Spanish food idioms, like ‘darse pisto’, ‘tener mala uva’, or ‘cortar el bacalao’. The results show that idiomatic meaning is based on metaphoric amalgams as well as metonymic chains, or even on the metaphor-metonymy interaction.