Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
In a large mixing bowl, cream together the softened butter, brown sugar, and granulated sugar until light and fluffy. This should take about 2-3 minutes.
Beat in the egg and vanilla extract until well incorporated.
In a separate bowl, whisk together the flour, baking soda, and salt. Gradually add the dry ingredients to the wet mixture, stirring until just combined. Be careful not to overmix.
Fold in the semi-sweet and milk chocolate chips until evenly distributed throughout the dough.
Using a cookie scoop or two tablespoons, drop rounded balls of dough onto the prepared baking sheet, spacing them about 2 inches apart.
Bake in the preheated oven for 10-12 minutes, or until the edges are lightly golden but the centers are still soft. Do not overbake, as the cookies will continue to cook as they cool.
Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.
Notes
Serve the cookies on a rustic wooden platter, dusted with a light sprinkle of sea salt for an added touch, and pair with a glass of cold milk for a delicious finish!