You can have trait/interface. But since garnish will be doing different thing it is OK to have two implementation. FP looks nice in theoretical examples in real world not so much.
In FP you will end with garnishFingerFood and garnishCocktail because you need to encode somewhere a specifics of garnish action. In OOP you will have garnish methods on Coctail and FingerFood and specifics and related knowledge how you need to perform garnish will be on object itself.
OOP is really powerful concept but failing in languages that have shit implementation. Java, C++ forsake OOP principles for "performance" or are made by people that do not understand concepts (Python, PHP).
In FP you will end with garnishFingerFood and garnishCocktail because you need to encode somewhere a specifics of garnish action. In OOP you will have garnish methods on Coctail and FingerFood and specifics and related knowledge how you need to perform garnish will be on object itself.
OOP is really powerful concept but failing in languages that have shit implementation. Java, C++ forsake OOP principles for "performance" or are made by people that do not understand concepts (Python, PHP).