Is it flavoured or flavored?
In British English, the adjective is spelled flavoured, and in American English, it is spelled flavored. This is also the spelling for the simple past tense form and past participle.
The same is true of other forms of the verb flavour/flavor: flavours/flavors, flavouring/flavoring.
You can use the QuillBot Grammar Checker to ensure you have the correct spelling of flavour or flavor.