This sauce is an excellent accompaniment to grilled meats, including sausages, as well as cold meats (beef, tongue, pork, ham) and smoked fish (salmon, sprats). You can find this recipe and others in the article Siberian Hot Stuff By Sharon Hudgins
3 tablespoons prepared horseradish (drained before measuring)
1/2 cup pure sour cream (containing no additives)
1/2 cup full-fat mayonnaise
1 1/2 teaspoons cider vinegar
1 Granny Smith apple, peeled, cored, and shredded
1/4 teaspoon sugar (optional)
Put the horseradish into a sieve and press as much liquid as possible out of it before measuring it. Combine all ingredients in a small glass bowl and whisk them together until well mixed. Cover and refrigerate at least 1 hour before serving.