1. Make dressing: In a medium bowl (or jar with a screw-top lid) combine shallot, mustard, vinegar, sugar and a pinch each of salt and pepper; mix (or shake) to combine. Slowly whisk in olive oil until dressing is emulsified (or add all at once and shake to combine).
2. Make salad: Place greens, endives and herbs in a large bowl and drizzle with about half of dressing. Using your hands, gently toss. Taste and, if desired, add remaining dressing and season with additional salt and pepper.