I answer with “Baruch Hashem good,” or something similar. (If you asked me right now I would say, “Baruch Hashem I have a headache.”)
I never ask “how are you,” unless I want to know. So when said friend answers “Baruch Hashem,” I get really upset. THAT’S NOT AN ANSWER. I then have to follow with “Baruch Hashem good or baruch Hashem bad?”
As an aside, I used to have a doctor who was best friends with my boss. One day he called my boss at work, I answered the phone, and of course, he asked, “How are you?” I answered, “Are you asking to be friendly, in which case I’ll say, ‘Fine, thank you,’ or are you asking as my doctor, in which case I’ll tell you the truth?”