In a medium bowl, whisk together the balsamic vinegar, Dijon mustard, honey, and salt until fully combined.
Gradually whisk in the olive oil, adding 1 tablespoon at a time and whisking until it incorporates, until an emulsion forms. Taste and if you like a sweeter dressing, you can whisk in a bit more honey. Serve immediately. Store refrigerated and bring to room temperature before serving (keeps at least 2 weeks).