Before you begin: the sauce needs at least 1 hour in the fridge.
Add all of the ingredients to a bowl and mix well. If you like, save some of the chives to sprinkle on top before serving.
1 cup sour cream, 1/4 cup prepared horseradish, 1 tablespoon Dijon mustard, 1 teaspoon white wine vinegar, 1/2 teaspoon Worcestershire sauce, 1/2 teaspoon salt, 1 tablespoon chives
Cover and refrigerate for at least 1 hour. Taste and add more salt or horseradish if you want.
Notes
Heat: for a milder sauce, start with half the horseradish and add more after tasting. For a hotter one, add more a tablespoon at a time.Make ahead: make it up to 1 day ahead.Storage: keep it covered in the fridge for up to 5 days, and don't leave it out for more than 2 hours. Don't freeze it; sour cream turns grainy once it thaws.Gluten-free: check the labels on your Worcestershire sauce, Dijon mustard and prepared horseradish. Some Worcestershire sauces are made with malt vinegar, which contains gluten.