Bring a pot of water to a boil over high heat, then add cubed red potatoes and boil until tender, 10–20 minutes, until a knife slides in easily. Visual cue: the cubes should look soft at the center with no firm core.

Drain the red potatoes and spread them out to cool until no longer steaming, about 10–15 minutes. Visual cue: they should look dry on the surface and feel room temperature.

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

Season with salt and pepper to taste, whisking until fully incorporated. Visual cue: the dressing thickens slightly and looks glossy.

Combine the cooled red potatoes with fresh chives and fresh parsley, tossing gently to distribute the herbs. Visual cue: green flecks should be visible throughout the potatoes.

Pour the dressing over the potato mixture and toss well until every piece looks coated. Visual cue: the potatoes should take on a creamy, pale color with a faint pink tint from the horseradish.

Refrigerate the potato salad for 2 hours to set the flavors before serving. Visual cue: it will look thicker and more cohesive after chilling.