Finely mince 1 medium shallot or 1 clove garlic and place into a jar or other container with a tight-fitting lid. Add 1/2 cup acid, 1/2 cup oil, 2 tablespoons sweetener, 1 tablespoon Dijon mustard, 1/2 teaspoon kosher salt, and 1/2 teaspoon black pepper. Seal the jar and shake vigorously until well-combined and the sweetener is dissolved. Use immediately or store in the refrigerator until ready to use.