Black and White Pinwheels recipe.

Ingredients
1 1/2 cups sifted all-purpose flour
1/2 teaspoon baking powder
1/2 teaspoon salt
1/2 cup butter, softened
1/2 cup white sugar
3 tablespoons milk
1/2 teaspoon vanilla extract
6 ounces semisweet chocolate chips

Directions
Sift together the flour, baking powder and salt; set aside.
Blend together the butter and the sugar, beat in the egg yolk, milk and vanilla. Add the flour mixture. Mix to combine.
Divide dough into two parts. Leave one part buttery and yellow, the other half is to have melted chocolate chips added to it. (Melt in microwave or over boiling water in double boiler being very careful not to scorch or burn). Chill both halves of the dough.
Roll out the black and white sections separately, each between two sheets of waxed paper. Roll into rectangles with 1/4 inch thickness. Place black on white roll together as tough rolling a jelly roll, removing center wax paper as you go. Shape into uniform roll, Chill dough for up to one hour.
Preheat oven to 400 degrees F (205 degrees C).
Slice chilled dough into 1/8 inch thick slices. Bake on ungreased cookie sheets at 400 degrees F (205 degrees C) for 5 to 7 minutes.