In a small bowl, stir together mayo, mustard, water, lemon juice, garlic, and salt together in a bowl.
The brand of mayo and dijon mustard you use can definitely impact the finished flavor of this sauce. Some mayos in particular are more on the sweet side. (I personally find that many avocado oil based mayos are.) And while that's totally fine, be sure to taste the sauce and add more salt or water to balance out the sweetness or reduce the strength of the mustard flavor if necessary.This is a really easy recipe to double if you're serving a large crowd or reduce by half if you're only feeding a family of four. Store any leftover sauce (if you have any) in an airtight container in your refrigerator.