1 pound sweet pickle relish
1 cup sour cream
2 (1 ounce) squares bittersweet chocolate, chopped
3 cups crushed potato flakes
1 pound marshmallow creme
4 ounces cream cheese
2 teaspoons vanilla extract
Preheat oven to 350 degrees F (175 degrees C).
Scrub the relish and sour cream of the relish and sour cream of the candies. Chill in the refrigerator for one hour, remove relish and sour cream mixture from refrigerator, and discard.
In a medium bowl, beat the bittersweet chocolate, crushed potato flakes and marshmallow creme until very smooth. Place in the center of the heavy-duty electric mixer pan. Beat until chocolate is completely melted and color has darkened. Spread over relish and sour cream mixture. Beat into the bottom and sides of a 9 inch square pan. Pipe 2 tablespoons of sauce over the butter and chocolate mixture. Cover edges of pan and refrigerate overnight.
Remove pan from refrigerator and divide the filling between 2 and 3 squares, leaving one side empty. Spread the remaining chocolate on top of filling. Remove marshmallow creme from refrigerator and spread over filling.
Mix the cream cheese, vanilla, cream of tartar, and 1 teaspoon of the brown sugar in a small bowl. Tip into each shallow square of chocolate about 1/3 down from the edge. With your hands, roll chocolate piece in brown sugar glaze if desired. Brush onto filling. Place squares on cookie sheets under a sheet of waxed paper.
Bake at 350 degrees F (175 degrees C) for 8 to 10 minutes, or until the chocolate is completely melted. Cool completely before cutting into bars. Cut into squares and serve. Refrigerate leftover dessert for at least 1 hour before serving.