Creamy Horseradish Sauce

This excellent horseradish sauce goes well with roast beef and is an especially good side to this  prime rib recipe. Horseradish holds a special place in my heart, searingly hot for a brief moment, and then the subtle vinegar after taste. I like straight prepared horseradish on occasion rather than sauce, however most of my family and guests prefer this mellow sauce. The heat and fire of the horseradish is tempered by the sour cream and the secret ingredient, applesauce.