3tablespoonsbottled white horseradish (not drained)
1tablespoonwhite-wine vinegar
1teaspoonsugar
3/4teaspoonsalt
1/2teaspoonblack pepper
1/3cupchopped fresh chives
3 lbcooked small (2-inch) boiling potatoes, cooled to room temperature and quartered
Whisk together mayonnaise, sour cream, horseradish, vinegar, sugar, salt, and pepper in a large bowl until smooth. Add chives and potatoes and stir to coat.