Preheat your oven to 350°F (175°C) and line two baking sheets with parchment paper.

In a large mixing bowl, cream together softened butter with granulated and brown sugars until light and fluffy.

Add the egg, vanilla extract, and orange zest, mixing until well combined.

In a separate bowl, whisk together the flour, baking soda, and salt. Gradually mix this into the wet ingredients.

Gently fold in the dark chocolate chunks.

Portion out the dough onto the prepared baking sheets, spacing them at least 2 inches apart.

Bake for 9–11 minutes until edges are golden brown and centers remain slightly soft.

Let cookies cool on the baking sheet for about 5 minutes before transferring to a wire rack.

If desired, sprinkle with flaky sea salt and additional orange zest before serving.