Melt 2/3 cup chocolate and stir until smooth. Sift flour, cocoa, baking soda and salt into medium bowl. In a large bowl, cream the butters and sugars. Add melted chocolate and mix well. Add egg and vanilla extract, and mix well blended. Add dry ingredients and, mix until just blended. Gently fold in chocolate chips. Using a 1/4cup disher (cookie baller or ice cream scoop) or measuring cup, drop onto parchment or silpat lined baking sheets.