What kind of sauce did I "invent"? One day I had an idea for a special "sauce" to use on (chicken) burgers. The basic idea was to give it some sort of "salad dressing" like taste.

The basic ingredients are cream cheese, mustard, vinegar and freshly ground black pepper. Plus a bit of salt and maybe some herbs I had lying around (mainly tarragon).

Now, I know I probably didn't invent something completely new, so my question is, what kind of sauce have I created? Are there similar widely known (named) ones?
Assuming you didn't over-use the vinegar, and mainteined the spreadable consistency of the cream-cheese, I think what you've invented is also known as a sandwich spread.