Boil carrot juice in a large, wide pot over medium-high heat, stirring often, until reduced to 1/3 cup, 25 to 30 minutes. Pour into a small bowl and let cool. Whisk in ginger, miso, vinegar, and oil.
Make ahead: Up to 2 weeks, chilled.
Note: Nutritional analysis is per Tbsp.
Servings 0
* Percent Daily Values are based on a 2,000 calorie diet. Your daily value may be higher or lower depending on your calorie needs.