Classic French Silk Pie - cooking recipe

Ingredients

1 c. sugar
3/4 c. butter, softened and cooled*
3 (1 oz.) sq. unsweetened chocolate, melted and cooled
1/4 tsp. cream of tartar
3 eggs
1 1/2 tsp. vanilla

Preparation

Beat granulated sugar and butter until light and fluffy. Stir in vanilla, cream of tartar and chocolate.
Beat in eggs until light and fluffy, about 3 minutes.
Pour into pie shell. Refrigerate until set.