In a large mixing bowl, combine butter and brown sugar until a uniform paste is achieved. I suggest cutting the butter into smaller pads to make mixing easier. Next, add the egg and mix again until uniform.
Add the flour, baking powder, baking soda and salt. Mix until a cookie dough is formed. Finally, add the chocolate chips and walnuts and mix until evenly distributed.
Shape and place on a baking sheet lined with plastic wrap. Chill in the fridge for 30 minutes.
Preheat oven to 350°F. Remove cookies from fridge and place on a baking sheet lines with parchment paper.
Bake in 350°F oven for 12 – 15 minutes. If cookie dough is frozen, bake for 18 – 20 minutes.
