Put all ingredients except oil in a mixing bowl and whisk well until everything is well combined and all salt is dissolved. At this point before you add the oil is when you want to adjust your seasonings. (It's much easier to taste everything without the oil.)
Add olive oil and whisk well again until all ingredients become incorporated. The mustard works to emulsify the dressing and keep the oil and vinegar from separating.
That's it!
Toss with your favorite greens (I like anything that has arugula in it.) We had it with pan-fried salmon with olive oil-confited tomatoes on top the other night.
