In a large mixing bowl, whisk together the melted butter, sugar, and brown sugar.
Whisk in the egg and vanilla extract until just combined.
Whisk in the molasses until just combined.
Fold in the dry ingredients, chocolate chips, and chopped pecans. Chill in the fridge for 30 minutes.
Scoop the dough onto a lined baking tray. Chill for another 30 minutes. Then bake at 350 for 11-12 minutes.