What's a good vegetarian substitute for Worcestershire sauce?
I have found a few recipes on the web:


Vegan Worcestershire sauce
Vegetarian oyster sauce


There are also a few hard to find ready-made vegan Worcestershire sauces on the market, such as Annie's.

When I read these recipes (which I have never made) I can tell that their flavor profile is missing some key aromas present in the original Worcestershire sauce. As strange as it may sound these sauces could use some of the aromas found in Parmigiano-Reggiano and in broccoli.  Whichever recipe works out, someone should write a blog post on this topic.