Wash potatoes and cut into 1" cubes. In a covered saucepan, boil potatoes in enough water to cover for 20 to 25 minutes or until just tender. Drain and cool.
In a large bowl, mix sour cream, mustard, vinegar, pepper, and chopped vegetables until combined. Add in cooled potatoes and mix to combine.
Cover and refrigerate for at least one hour prior to serving.
Recipe by SoFabFood at https://sofabfood.com/skinny-mustard-potato-salad-recipe/