Pre heat oven at 350 degrees.
Add butter, egg, vanilla, and sugar together in bowl. Use mixer until ingredients are creamed together.
In separate bowl combine your dry ingredients. Flour, baking soda, cocoa powder, and salt. After dry ingredients are mixed together, add your dry mixture to your wet mixture.
After cookie dough is mixed together, fold in walnuts and chocolate chips.
I cooked my cookies on my top rack in an electric oven. They ended up being perfect at 8 minutes. 8 minutes they were soft and chewy. 10 minutes still chewy but a crispier bottom.