Heat the oven to 350° F, and prepare your cookie sheets with either parchment paper or a silicon mat.
Break up the 8 ounces of chocolate into smaller pieces and add the butter to a large mixing bowl set over simmering water (bain-marie). Stir often until completely melted and smooth.Note: I prefer to melt chocolate over a bain-marie so I don't have to worry about the chocolate burning in the microwave.
Remove the bowl from the bain-marie and let cool for five minutes
Add the sugar and egg to a large mixing bowl, and mix on medium speed for one minute.
Add the melted chocolate and vanilla to the bowl, and mix for two minutes on medium speed to fully mix the ingredients.
In a small bowl add the flour, baking powder, baking soda, salt, and espresso powder, mix well then add this to the chocolate butter mixture. Mix to incorporate the flour.
Add the 6 ounces of chocolate chips and stir in with a heavy spoon.
Using a 1-inch cookie scoop, drop the dough onto the cookie sheets. This is about one tablespoon of raw dough.
Bake for 9 - 10 minutes or until the edges are set, and the centers are still slightly soft.
Remove from oven and place on cooling racks.
Store the cookies in an airtight container for several days.
Notes
For melting the chocolate you can use a block of chocolate that has been chopped, chocolate wafers that are thin disks, or chocolate chips.For scooping the cookies, I like using a 1 inch cookie scoop that helps make all the cookies the same size and perfectly round.You can freeze the uncooked dough balls. Simply make the dough balls, place them in the freezer on a tray, and once frozen place the dough balls in a freezer bag for up to six months.How to bake the frozen cookie dough:
You can let the dough balls thaw on the cookie sheet and bake as directed in the recipe.
To bake frozen cookie dough, place the frozen dough balls on the cookie sheet. Reduce the oven temperature to 325 degrees F., then add an extra 2-3 minutes to the baking time.