1 tsp. Dijon mustard
1 tsp. finely-chopped shallot
3 Tbls. red wine vinegar
Kosher or sea salt and freshly-groud pepper, to taste
1/3 c. extra-virgin olive oil

In a small bowl (or in your serving bowl), whisk together the mustard, shallot, vinegar, salt and pepper. Add olive oil and continue whisking until emulsified. Season to taste.