Preheat your oven to 350°F (175°C). Line two baking sheets with parchment paper.
In a large mixing bowl, cream together the softened butter, granulated sugar, and brown sugar until light and fluffy using an electric mixer.
Beat in the eggs one at a time, followed by the vanilla extract and espresso powder, mixing until well-combined.
In a separate bowl, whisk together the flour, baking soda, and salt. Gradually add this dry mixture to the wet ingredients, mixing just until combined. Be careful not to overmix.
Fold in the chocolate chips and chopped walnuts (if using) using a spatula until evenly distributed throughout the dough.
Use a cookie scoop or tablespoon to drop rounded portions of dough onto the prepared baking sheets, leaving space between each cookie as they will spread while baking.
Bake in the preheated oven for 10-12 minutes, or until the edges are golden and the centers look slightly underbaked—they will continue to cook on the baking sheet after removing from the oven.
Allow the cookies to cool on the baking sheets for 5 minutes before transferring them to a wire rack to cool completely.
Notes
Serve warm with a side of espresso or milk. Arrange cookies on a rustic wooden board and sprinkle a dusting of powdered sugar for a charming finish. Enjoy!