Preheat oven to 350 degrees F and line two baking sheets with parchment paper.
In a mixing bowl, stir together all ingredients except for chocolate to form a smooth dough.
Using a heaping teaspoon, spoon balls of dough onto cookie sheets. Round off the tops a little bit with your fingertips or the back of a spoon.
Bake for about 9 to 11 minutes or until they appear set, then transfer to a wire rack to cool.
Melt the chocolate and butter in the microwave using 50% power and stirring every 30 seconds. Spoon a little chocolate over the top of each cookie.
Put the cookies in the refrigerator until the chocolate is set.
You can make halve a batch by using 2 tablespoons of beaten egg