Mix together the butter and sugars until combined. Add the egg and vanilla until combined.
Add baking soda, salt, and dark chocolate powder until mixed. Add the chips and walnuts and stir until combined. This mix is very thick.
Use a cookie scoop to place cookie dough on a baking sheet and cook for 10 minutes until set on the edges. The center will still be gooey when you take them out of the oven. Let cook for 15 minutes before removing to a cooling rack to completely cool.
Notes
NOTE: I have also added 1/2 a cup of Peanut Butter chips to this recipe. If you don't have Dark Chocolate powder, regular cocoa powder will work well.