Ingredients

• 1 cup (2 sticks) unsalted butter, at room temperature
• 1 1/4 cups sugar
• 1 egg
• 1 teaspoon vanilla extract
• 2 1/4 cups all-purpose flour
• 1/4 teaspoon salt
• 1 1/4 teaspoons baking powder
• 1 square unsweetened chocolate, melted and cooled, or 3 tablespoons unsweetened cocoa mixed with 1 tablespoon melted shortening
• 1/4 cup very finely chopped pecans or walnuts
• Red food coloring

Instructions

1. Cream butter on medium speed until light and fluffy. Gradually add sugar, beating well. Add egg and vanilla and beat well. Whisk together flour, salt, and baking powder; then add to batter and mix well to make a fairly stiff dough.
2. Divide dough into 3 equal parts. Stir melted chocolate and nuts into one part. Knead a few drops of red food coloring into a second part. Leave the third part plain.
3. Line a 9-by-5-by-3-inch loaf pan with waxed paper. Press the plain part of the dough evenly over bottom of pan, packing dough in firmly. Spread the chocolate layer evenly over that. Top with the pink layer and spread until smooth.
4. Fold waxed paper over the top of the dough and press gently with fingers to smooth out top and press layers together. Refrigerate for 12 to 24 hours, until very firm.
5. Preheat oven to 350 degrees F. Turn dough out onto a clean cutting board and peel off the waxed paper. Cut the loaf in half lengthwise, then cut each portion of dough into 1/8-inch slices. Place about 1 inch apart on ungreased cookie sheets. Bake for about 10 minutes, until set. Cookies should not brown. Let stand on cookie sheets for a few seconds, then remove to wire racks to cool.