Preheat the oven to 360°F.
Cream the butter and sugars until light and fluffy (5 minutes on medium speed if using a mixer). While the butter and sugar is creaming, whisk together the flour, baking soda and salt in a small bowl. Set aside.
Add the egg and vanilla to the butter-sugar and mix until combined. Add the flour and mix, with a spatula, until barely combined. Fold in the chocolate. Portion the cookies out onto a parchment paper lined cookie sheet. Sprinkle with the flaky salt and bake for 12 minutes, until the edges are golden but the centers are gooey. Let cool on the baking sheet for 5 minutes and enjoy warm!
