2/3 Dukes Mayo, 1/3 white vinegar, lots of ground black pepper. You can either shake it up or blend it. Make it a few hours ahead of time and let sit in fridge.
Think Jim&Nick's must use this one. Ate there a couple weeks ago and there was so much black pepper you couldn't taste anything else. Truly nasty stuff. So I will say add black pepper to taste. I never measured mine. I just spoon out the mayo. Then add the vinegar till it looks right. Then add the pepper. I have a friend that puts a little splash of buttermilk in his...I can't taste the difference.