Place minced shallot and Dijon mustard into a non-reactive bowl. Put balsamic vinegar, sea salt and ground black pepper into the bowl and whisk to mix well. Very slowly add the olive oil while whisking vigorously until all the oil is incorporated and the vinaigrette smooth and creamy. Store excess in a covered container in the refrigerator for up to 7 days.
Note: You can easily vary the oil and vinegar selections to make other flavored vinaigrettes. See The Olive Tap "Perfect Pairings" for ideas.
