Gather all your ingredients. Mince the red onion finely and chop the fresh dill.
In a medium mixing bowl, combine the Dijon mustard, honey, and rice vinegar. Whisk until well blended and smooth.
Stir in the minced red onion and chopped dill, along with the ground black pepper. Mix until evenly distributed.
Slowly drizzle in the olive oil while whisking continuously to emulsify the sauce.
Taste and adjust sweetness or tanginess with honey or vinegar as desired.
Transfer the sauce to a storage container, seal, and refrigerate for at least 30 minutes to let the flavors meld.
