Place ½ cup semi-sweet chocolate chips and 2 Tbsp butter in a small microwave-safe bowl and microwave on high for 1 minute. Stir until melted. [You can also melt together on the stovetop on LOW).
Place ⅓ cup all-purpose flour, 2 TBSP cocoa powder, ½ TSP instant coffee granules, ¼ TSP kosher salt, and 1/8 TSP baking soda in a small bowl and STIR to combine.
Place ¼ cup plus 2 TBSP sugar plus 1 large egg in a large bowl and whisk until the sugar has dissolved, about 2 minutes. Add the melted chocolate mixture and stir to combine.
Add in the flour mixture, folding together with a wooden spoon. Add ½ cup chopped walnuts and fold until combiined.
Place in the fridge for 20 minutes to chill the dough.
Prheat the oven to 375°F and line 2 baking sheets with parchment paper.
MAKING CHOCOLATE CHIP DOUGH:
Place 1 cup plus 2 TBSP all-purpose flour, ½ TSP kosher salt, and ¼ TSP baking soda in a medium bowl and STIR to combine.
Using a stand mixer or hand mixer, mix together the softened butter, ½ cup packed light brown sugar, and ¼ cup granulated sugar, beating on medium speed until combined. Add 1 large egg and 1 tsp vanilla extract and beat until combined, 2 to 3 minutes. Add the flour mixture and beat on low speed until just combined.
Add ¾ cup milk chocolate chips and fold in by hand with a wooden spoon until combined. Pop in the fridge and keep cold until the brownie dough is ready, at least 10 minutes.
MAKE THE BROOKIE COOKIES:
Make 24 balls with the chocolate chip dough (about 1-tablespoon each) and place on the baking sheets, 12 per sheet. Do the same with the brownie dough, making 24 balls, placing each one right next to the chocolate chip dough.
Spray your hands with cooking spray so the dough won’t stick to your fingers. Quickly roll each brownie and chocolate chip portion of the dough together with your hands to form 24 half-balls with each kind of dough. Arrange at least 2-inches apart on the baking sheets. TIP: Try to get the “seam” with showing the light and dark dough facing up, so all the cookies look the same when baked.
Bake cookies for 7 minutes, and rotate the baking sheets. Continue baking 5-8 more minutes until the edges of the chocolate chip side are golden brown and the cookie will be “cracked" on top. Remove from the oven and allow the cookies to cool for a few minutes before transferring them to a wire rack.