Horseradish Potato Salad with Deli Roast Beef

In 3-quart saucepan, place potatoes and enough water to cover; heat to boiling over high heat. Reduce heat to low; cover and simmer 10 to 12 minutes or until potatoes are fork-tender. Drain; cool slightly.

Meanwhile, reserve some chives for garnish; cut remaining chives into 3/4-inch pieces. In large bowl, whisk cut chives with sour cream, horseradish, salt, pepper, and shallot.

When potatoes are cool enough to handle, cut each in half or into quarters if large. Add warm potatoes to sour-cream dressing in bowl; with rubber spatula, stir gently until coated with dressing. Let potato mixture stand 30 minutes at room temperature to absorb dressing, stirring occasionally. Serve potato salad warm or cover and refrigerate up to 1 day to serve cold.

To serve, arrange roast beef and potato salad on large platter. Garnish with reserved chives.