Preheat the oven to 375°. Melt the butter and chocolate in a microwave oven on High for 30 seconds. Stir the sugar into the chocolate. Let cool. Stir in the egg and vanilla. In separate bowl whisk together the flour, baking soda and salt, Stir into chocolate until smooth. Drop teaspoons of the dough about 2 inches apart onto cookie sheet. Sprinkle with sugar. Press with fingers. Bake for about 15 minute. Transfer to a rack to cool. (The cookies can be kept for up to 3 days in airtight container.) cook 56