white wine vinegar
tablespoon finely chopped fresh tarragon
whole grain mustard
extra virgin olive oil
sea salt and freshly ground pepper
In a small bowl, combine the vinegar, shallot, and tarragon. Let sit 5 minutes.
Stir in the mustard. In a thin, steady stream, add the olive oil, whisking constantly, until the dressing thickens. Season with salt and pepper.