Combine all the ingredients for the dressing in a mini blender or food processor and process until smooth and creamy, about 1 minute. Adjust thickness by adding more milk, if necessary.
Arrange the arugula at the bottom of a shallow bowl or large plate. Top with shaved endive, radicchio, pear, blackberries, crumbled blue cheese and walnuts.
Pour as much or a little dressing as you want all over your gorgeous salad, toss and enjoy!
*Since pears and endives have a tendency to brown pretty quickly once exposed to air, I recommend that you start by making the dressing and also deal with them last when prepping your ingredients for the salad.