4 oz. unsweetened chocolate, chopped
3 c. semi-sweet chocolate chips
1 stick (1/2 c.) unsalted butter, cut into pieces
1/2 c. all-purpose flour
1/2 tsp. double-acting baking powder
1/2 tsp. salt
4 lg. eggs
1 1/2 c. sugar
1 1/2 tbsp. instant espresso powder (or 2 to 3 tbsp. instant coffee)
2 tsp. vanilla

In a metal bowl set over a saucepan of barely simmering water, melt the unsweetened chocolate, 1 1/2 cups of the chocolate chips and the butter, stirring until the mixture is smooth, and remove the bowl from the heat.

In a small bowl stir together the flour, the baking powder and the salt. In a large bowl beat the eggs with the sugar until the mixture is thick and pale and beat in the espresso powder and the vanilla. Fold the chocolate mixture into the egg mixture, fold in the flour mixture and fold in the remaining 1 1/2 cups chocolate chips.

Let the batter stand for 15 minutes. Drop the batter by heaping tablespoons about 2 inches apart onto baking sheets lined with parchment paper and bake the cookies in batches in the middle of a preheated 350 degree oven for 8 to 10 minutes, or until they are puffed and shiny and cracked on top. Do not overbake. Let the cookies cool on the sheets for 5 minutes, transfer them with a metal spatula to racks, and let them cool completely. Make about 36 cookies.