Preheat the oven to 350F and line a large baking sheet with parchment paper.
In a medium bowl, whisk together the flour, baking soda, baking powder, salt, and cinnamon. Set aside.
In a large bowl, cream together the melted butter and sugars either by hand or using an electric mixer. Keep mixing on medium high speed until the mixture lightens and thickens (about 3 minutes, see picture in post for reference).
Mix in the vanilla and egg until smooth.
Dump in the dry ingredients and mix to combine.
Fold in the chips and nuts using a rubber spatula.
Scoop the cookies out on to the baking sheet, spacing them a few inches apart as they spread quite a bit. Use a regular cookie scoop (2 tablespoons) for the best results.
Bake for 10-12 minutes or until the edges are a light golden brown and the center is pale and puffed. The cookies will continue to bake and settle once they’re out of the oven so it’s ok if they look a little underdone.
Sprinkle with a little sea salt and transfer to a cooling rack. Let them cool for about 10 minutes then dig in!
