In a metal bowl set over a saucepan of simmering water melt the
unsweetened chocolate, 1 1/2 cups chocolate chips and butter, stirring
until mixture is smooth. Remove bowl from heat.
In a small bowl, stir together flour, baking powder and salt. In a bowl beat together eggs and sugar until mixture is thick and pale. Beat in espresso powder and vanilla. Fold chocolate mixture into egg mixture, fold in flour mixture and stir in remaining 1/2 cup chocolate chips. Let batter stand 15 minutes. Drop by heaping tablespoonfuls about 2 inches apart onto baking sheets lined with parchment paper. Bake 8 to 10 minutes at 350 degrees F. until puffed, shiny and cracked on top. Do not over bake. Let cool on
baking sheets for 5 minutes, transfer to racks and let cool completely.
Makes 36 cookies.