Bring a large pot of water to a boil and add the cubed red potatoes; boil for 10-15 minutes at a rolling simmer until tender and easily pierced. Visual cue: potato cubes should slide off a knife with little resistance.

Drain the potatoes in a colander and cool them until no longer steaming, about 10 minutes. Visual cue: the cubes look dry on the surface and are room-temperature to the touch.

In a mixing bowl, whisk together sour cream, mayonnaise, prepared horseradish, Dijon mustard, and white wine vinegar until smooth. Visual cue: the sauce turns creamy and evenly speckled from the horseradish.

Season the dressing with salt and pepper to taste. Visual cue: a spoon dragged across the surface shows consistent seasoning with no dry pockets.

Combine the cooled red potatoes with fresh chives and fresh parsley in a large bowl. Visual cue: herbs are distributed so green flecks are visible throughout the potato cubes.

Pour the dressing over the potato mixture and toss until every piece is coated. Visual cue: the salad looks glossy and creamy rather than dry.

Refrigerate the potato salad for 2 hours, uncovered or loosely covered, to let flavors meld. Visual cue: the dressing thickens slightly and clings to the potatoes.