I am a non-native speaker of English, and I would appreciate if anyone could be so kind as to answer a quick grammar question that I have. Please, read the sentence below:

One of my favorite hobbies is/are soap operas.

My question is, should the sentence read 'is' or 'are'? I am very unsure about this particular example. I would also very much like to have an explanation to why 'is' or 'are' should be applied. Thanks for any help you can provide!

Heni