iPhone Call, I Accidentally hung up

So, I got a call on my phone from a number that was not a contact, but it wasn’t a No Caller ID either, meaning I saw the number and everything. Looked convincing so I answered, they were breaking up a bit, but it sounded like my friend. I accidentally clicked hang up and I want to call them again. How do I find their number? They weren’t a contact, weren’t anonymous, but I forgot their number.