1 cup smooth peanut butter
2/3 cup butter, softened
1 teaspoon vanilla extract
2 cups firmly packed light brown sugar (push through
a sieve to remove any lumps)
3 eggs
1 cup all-purpose flour
1/2 teaspoon salt
3/4 cup powdered sugar
2 teaspoons water
2 squares semi-sweet chocolate OR 1/4 cup
Semi-sweet chocolate pieces plus 1 teaspoon
Shortening, melted
Combine peanut butter and butter in a large bowl and beat until light and fluffy. Add brown sugar and continue to beat for 1 to 2 minutes. Beat in eggs, one at a time, then add vanilla. Stir in flour and salt just until well blended.
Spread batter in greased or foil lined 13×9-inch baking pan. Bake in preheated 350°F oven for 35 minutes, or until center springs back when lightly touched with fingertip. Allow to cool slightly.
Combine powdered sugar with water in a small bowl and stir until smooth. Drizzle from a spoon over still-warm cookies in pan. Swirl with a spoon to make random pattern.
Melt chocolate in a small zippered, plastic bag for one minute in microwave. Knead with fingers to make sure it is melted. Return to microwave for a few additional seconds if necessary. Chips may take a little longer. Snip a small tip from one corner and drizzle over white glaze in a random black and white pattern.
When cool, use a sharp knife to cut into 36 rectangles.
Cover and store in refrigerator.