Pork Tenderloin with Mustard Sauce

    1/3 cup red wine
    1/3 cup soy sauce
    2 tablespoons light brown
    sugar
    2 pounds pork tenderloin
    1/3 cup mayonnaise
    1/3 cup sour cream
    1 1/2 tablespoons mustard powder
    1 tablespoon minced fresh chives (optional)

Combine wine, soy sauce, and brown sugar in a large resealable
plastic bag. Place tenderloin in bag, and refrigerate overnight, or
at least 8 hours.

In a small bowl, combine mayonnaise, sour cream, mustard powder;
mix well. Mix in minced chives if you wish. Chill until ready to
serve.

Preheat oven to 325F. Place meat and marinade in a shallow baking
dish, and roast for 1 hour, basting occasionally. Temperature of meat
should register 160F. Let rest for a few minutes, then cut into
1/2 inch thick slices. Serve with mustard sauce.