To a bowl, add flour, baking soda, and salt. Pour melted butter into a separate bowl. Add sugar and brown sugar and whisk to incorporate. Crack eggs into bowl with butter mixture. Add vanilla. Beat to incorporate. Gradually pour dry ingredients into wet, mixing to combine. Add chocolate pieces and stir in. Cover dough. Chill overnight in fridge.
Preheat oven to 325 F (165 C). Spoon 60 gram scoops onto baking tray lined with parchment paper 7.5 centimeters apart. Bake at 325 F (165 C) for 25 minutes.