If the job description does not mention "Framework X," you should probably avoid answering that you use "Framework X" to solve the problem presented to you by the interviewer. If I ask you to perform a simple task, such as parsing a string in a well-known format, saying "Framework X does that for me" is likely to be seen as a negative.

You should be able to do the simple things in PHP itself (e.g. parsing strings). As interviewers, we generally care about your proficiency with the language, not with how much you like the framework of your individual choosing.

Saying that you use a feature of "Framework X" for simple things is a negative. It sounds like you're dependent on that framework for basic tasks. That means we (the employers) will need to train you how to do it without that framework, and that's a hassle for us.

One caveat here is that if the employer has already specified that they use "Framework X" then they probably do want to see that you're familiar with it. Alternatively, if you are going to be the only person on the team, you're also probably fine. But in collaborative, team environments, it is unlikely that the employer is already using the framework you, individually, prefer.
