1/4 cup shortening plus 1/4 cup
    butter or 1/2 cup margarine
1 cup brown sugar
1/2 cup granulated sugar
1 teaspoon vanilla extract
2 eggs
1/2 cup walnuts, chopped (optional)
2 3/4 cups all-purpose flour, sifted
1/2 teaspoon baking soda
1 teaspoon salt
1 cup sour cream
1 (1 ounce) square unsweetened chocolate, melted

Cream shortening and butter until light and fluffy. Beat in eggs. Stir in walnuts, if used.

Sift together flour, baking soda and salt and stir in alternately with sour cream. Divide dough in half and add chocolate to just one half. Drop cookie dough onto lightly greased pan about 2 inches apart. Drop white part side by side with chocolate part. The cookies will join while baking. Can be sprinkled with nuts before baking. Bake at 375 degrees F for 12 minutes.