Preheat your oven to 350°F (175°C).
In a large mixing bowl, beat the room temperature salted butter with both sugars until light and fluffy, about 2-3 minutes.
Add the large egg and vanilla extract to the butter mixture and beat until fully incorporated.
In a separate bowl, whisk together the flour, baking soda, and flaky sea salt. Gradually add to the wet ingredients, mixing until just combined.
Gently fold in the coarsely chopped chocolate and toasted nuts (if using).
Scoop tablespoon-sized portions of dough onto a baking sheet lined with parchment paper, leaving space between each cookie.
Bake for 10-12 minutes, until edges are golden brown and centers are slightly soft. Remove and sprinkle with flaky sea salt.
Cool on the baking sheet for about 5 minutes before transferring to a cooling rack.