START TO FINISH: 50 minutes
SERVINGS: 6
Scandinavians frequently combine potent smoked fish and mild, creamy potatoes. For this dish, we find a modest amount of sour cream both binds the salad and adds a tanginess that, along with the pungency of the horseradish, works well with the salty richness of smoked trout. Up the horseradish if you like. Tossing the potatoes with vinegar, salt and pepper immediately after draining them allows them to soak up the seasonings as they cool. Serve the salad on a bed of watercress, lettuce or your favorite greens. Leftovers can be refrigerated for a couple days; bring to room temperature before serving.
Don’t dress the potatoes until they’ve cooled to the point of barely warm to the touch. If the potatoes are hot, they’ll cause the dressing to break.
2 pounds red potatoes, cut into 1-inch pieces
Kosher salt and ground black pepper
6 medium radishes, halved and thinly sliced
5 tablespoons white wine vinegar, divided
½ cup sour cream
3 tablespoons prepared horseradish
2 tablespoons extra-virgin olive oil
8 ounces smoked trout, skin discarded, flesh broken into small flakes
2 tablespoons finely chopped fresh dill
6 tablespoons finely chopped fresh chives, divided
In a large saucepan, combine the potatoes and 2 tablespoons salt, then add enough water to cover by 1 inch. Bring to a boil over high, then reduce to medium-low and simmer until a knife inserted into the largest piece meets no resistance, about 20 minutes.
Meanwhile, in a small bowl, combine the radishes, 2 tablespoons of the vinegar and ¼ teaspoon salt. Toss and set aside. In a large bowl, whisk together 1 tablespoon of the remaining vinegar, the sour cream, horseradish, oil and ¼ teaspoon each salt and pepper. Refrigerate until needed.
When the potatoes are done, drain in a colander, then spread in an even layer in a large baking dish. Sprinkle with the remaining 2 tablespoons vinegar and ½ teaspoon each salt and pepper. Refrigerate, uncovered, until barely warm to the touch, about 20 minutes.
Add the cooled potatoes to the sour cream mixture and fold with a rubber spatula until evenly coated. Drain the radishes, discarding the liquid. Fold in the radishes, smoked trout, dill and 4 tablespoons of the chives. Taste and season with salt and pepper. Transfer to a serving bowl and sprinkle with the remaining 2 tablespoons chives.