1/4 cup white wine or champagne vinegar
1 teaspoon Dijon mustard
1 teaspoon Kosher salt
Generous pinch of ground black pepper
1 tsp finely minced shallot
2/3 cup extra virgin olive oil
Place all ingredients in a blender (or in a suitable container for use of an immersion blender).
Pulse 2-3 times to fully blend the ingredients.
With the blender running, gradually pour in 2/3 cup extra virgin olive oil.
Use immediately, or you may store it covered in the refrigerator until used.
Remember to use it sparingly, otherwise the dressing will cause your greens to go limp, and rather quickly, too.