This Greek sauce has a potato as the unusual base. I haven't tried this yet, I found the recipe in an old cookbook I've had for years, & thought it would be a perfect submission for the ZWT4 - let's hope it's a good one!
Peel potato and boil until tender. Put through a ricer or sieve. Measure 1/2 cup of potato & put in a bowl; mix in garlic and salt. Gradually add olive oil and vinegar alternately while beating with a spoon. Chill. Serve with meat or fish.