Chocolate Vinaigrette

I just got back from the American Wine Society annual meeting and had some wonderful wine. But what was most memorable was a wine and food pairing sessions where Tony Lawrence - Chef to You in Philidelphia - made a dessert of Field Greens, Blue Cheese, and Dried Cranberries with a CHOCOLATE VINAIGRETTE and brownie croutons. We all kept an open mind and it just blew us away.
Does anyone have a recipe for a chocolate vonaigrette? I asked him for the recipe at lunch that day amd he said “I could give it to you but then I would have to kill you!” I couldn’t even get it out of his wife.

HELP! This is a must make for my husbad if I can just figure out the recipe!