In Utah Is it legal to audio record a conversation with my employer without their knowledge?

I'm not sure why you went through this effort. It is not illegal to replace or fire someone. Your employer doesn't even need a reason, so even if they lied to you--it is not legally relevant. Also, regardless of what the law is on recording, your employer can fire you if they don't like the fact that you recorded them. Again, in a "at will" state they don't need a reason to let you go. Utah is an "at will" employment state. This means unless you're union (in which case get your rep involved) or have a contract that says otherwise, you can be fired at any time without just cause as long as it is not related to your race, religion, ethnicity, age, gender, disability, familial status, and not in retaliation for whistleblowing illegal conduct, taking FMLA leave, and filing for disability/workers compensation. Utah is a one party consent state, which means people can be audio recorded without their consent as long as the person doing the recording was a party to the conversation being recorded. So there will likely not be criminal or civil penalties for the recording, but your employer can fire you because of it, and again, even if the recording proves they were lying to you, it just doesn't matter in an "at will" state. They can fire you at any time without any reason. If you think your potential firing has to do with one of the protected categories above, then get a consultation with a local plaintiff employment attorney.