Light Dough
    1 1/3 cups flour
    1/2 teaspoon baking powder
    1/4 teaspoon salt
    1/2 cup butter, softened
    1/4 cup vegetable shortening
    1/2 cup each granulated sugar and firmly packed brown sugar
    1/2 teaspoon vanilla extract
    1 egg yolk

Chocolate Dough
    1 cup flour
    1/4 cup unsweetened cocoa
    1/2 teaspoon baking soda
    1/4 teaspoon salt
    1/2 cup butter, softened
    1/4 cup vegetable shortening
    1/2 cup each granulated sugar and firmly packed brown sugar
    1 egg

Prepare Light Dough: In a bowl, stir together flour, baking powder and salt to combine thoroughly; set aside. In mixer bowl, combine butter and shortening; beat to blend well. Add sugars and beat until fluffy. Beat in vanilla, then egg yolk. Gradually add flour mixture, beating until just blended.

Prepare Chocolate Dough: In a bowl, stir together flour, cocoa, baking soda and salt to combine thoroughly; set aside. In mixer bowl, combine butter and shortening; beat to blend well. Add sugars and beat until fluffy. Add egg and beat until well blended. Gradually add flour mixture, beating until just blended.

Assemble Pinwheels: Transfer Light Dough to a large sheet of plastic wrap or waxed paper. Using a spatula, flatten dough into a rectangle about 1-inch thick. Wrap tightly and refrigerate until firm (at least 2 hours or overnight; or place in freezer for 30 to 45 minutes).

Repeat procedure described in step 1 using Chocolate Dough. 

Place Light Dough between 2 sheets of plastic wrap; roll into a 12-by-16-inch rectangle. Remove top sheet of plastic.

Repeat procedure described in step 3 using Chocolate Dough. 

Invert Chocolate Dough over Light Dough; peel off top sheet of plastic wrap. Starting with a 16-inch edge and using bottom sheet of plastic and a spatula to guide dough, tightly roll the 2 sheets of dough together, jelly-roll fashion. Cut roll in half to make two 8-inch-long rolls. Enclose each tightly in plastic wrap; refrigerate for at least 3 hours or overnight.

Bake Pinwheels: Preheat oven to 350 degrees. Remove one roll of cookie dough at a time from refrigerator. Slice into cookies 1/4 -inch thick; arrange slices about 1 inch apart on ungreased baking sheets. 

Bake until cookies feel firm when touched lightly (8 to 10 minutes). Transfer to wire racks to cool.

Per serving: 91 calories; 5 g fat (2.5 g saturated fat; 49 percent calories from fat); 11 g carbohydrates; 16 mg cholesterol; 69 mg sodium; 1 g protein; 0.2 g fiber.

From Annette Gooch, Primary Colors.