Preheat oven to 350 F. and grease 2 large heavy baking sheets.
In a double boiler or a metal bowl set over a saucepan of barely simmering water melt unsweetened chocolate, 1 cup semi-sweet chocolate chips, and butter, stirring until smooth, and remove top of double boiler or bowl from heat. Learn different techniques for How To Melt Chocolate.
In a bowl with an electric mixer beat eggs, sugar, and ground coffee on high speed until very thick and pale and mixture forms a ribbon when beaters are lifted, about 3 minutes, and beat in chocolate mixture.
Into egg mixture sift in flour, baking powder, and salt and stir until just combined. Stir in remaining chocolate chips and walnuts. Let the batter rest for about 10 to 15 minutes (it will thicken slightly during this time).
NOTE: This cookie dough do not do well if you freeze the dough.
Drop batter by heaping tablespoons about 2-inches apart onto baking sheets and bake in batched on the middle rack of oven for 8 to 10 minutes, or until puffed and cracked on top.
Remove from oven and cool cookies on baking sheets 1 minute and then transfer to racks to cool completely. NOTE: DO NOT OVER BAKE - these cookies should be slightly soft in the centers.
* Buy good-quality chocolate. Remember, your cookies will only be as good as the chocolate you buy! like to use Ghirardelli Premium semi-sweet baking chips
** I substituted Ground Red Chipotle that I purchased from Penzeys Spices.
Chocolate Espresso Cookies Recipe: https://whatscookingamerica.net/Cookie/ChocEspressoCookies.htm