It is in Prevent and Reverse Heart Disease by Caldwell B. Esselstyne, Jr. M.D. page 169
Also in his son';s book called The Engine 2 Diet by Rip Esselstyne page234 but it is called Beam me up Scottie Dressing.
3 tablespoons balsamic vinegar
2 tablespoons any mustard
1 tablespoon maple syrup (or agave or honey)
Naturally most of us tweek this. I use less mustard, more syrup and a dash of water
Riva