Preheat oven to 350℉. Line baking sheets with parchment paper and them set aside.
Melt butter in a saucepan over medium-low heat. Once butter is completely melted, add half of your chocolate chips and stir constantly until the chocolate melts completely.
Remove saucepan from heat and stir in the milk, vanilla, instant coffee, and cocoa powder.
In a large mixing bowl, use an electric mixer to beat sugars and eggs on medium-high speed for 1-2 minutes, to combine.
Stir in the melted chocolate/butter mixture and beat on medium speed for 1-2 minutes, to combine.
In a medium-sized bowl, mix together flour, baking soda, and salt. Add half of this to your chocolate mixture and beat until combined, then add the second half of your flour mixture.
Stir in the second half of your chocolate chips.
Arrange 2-tablespoon sized scoops of dough about 3 inches apart on the prepared baking sheet.
Bake in preheated 350°F. oven for 7-8 minutes, until edges are set but centers are still slightly soft.
Allow cookies to cool on the baking sheet for 5 minutes before moving them to a cooling rack.
Notes
I recommend using an electric hand or stand mixer to make this recipe, because the dough is very thick and heavy.
Use medium-low heat when you melt the chocolate and butter. Otherwise, you'll risk scorching the chocolate.
Avoid over mixing the ingredients. To keep the cookies soft and chewy, it's important not to work the dough too much.
Be sure to preheat your oven. If the oven isn't hot enough, the dough will spread too much before the cookies begin to bake.
Leave space on the pan for the dough to spread. These cookies have a tendency to spread a little bit in the oven. To prevent the dough balls from baking into one giant cookie, leave at least 2 inches of space between each portion of dough.
Storage - Store in an airtight container in a cool, dry place for up to 5 days, or in the refrigerator for up to a week.
Reheating – If reheating from the freezer, let them come to room temperature on their own. Wrap them in a lightly moistened paper towel and then heat in the microwave for 15-30 seconds.