I always make my own, also.
I use
evoo
lemon juice
prepared mustard
Fresh or minced garlic
salt and pepper
It's very good. In fact, I left it in Dallas a couple of weeks ago when I visited and stayed with a (non-IP) friend. I called her when I realized I had left it and told her to go ahead an use it, since I wouldn't be back there until next month.
She emailed me that night to ask what was in it so she could make her own!