Preheat & Prep: Preheat the oven to 350°F (175°C). Line a baking sheet with parchment paper.
Mix Dry Ingredients: In a bowl, whisk together flour, baking soda, and salt.
Cream Butter & Sugar: Beat the butter and brown sugar until smooth and fluffy.
Add Wet Ingredients: Mix in the egg and vanilla extract.
Add Dry Ingredients: Gradually mix the dry ingredients into the wet mixture.
Fold in Macadamias and Chocolate Chips: Gently fold in the chopped macadamia nuts and chocolate chips.
Scoop Dough: Drop spoonfuls of dough onto the prepared baking sheet.
Bake: Bake for 10-12 minutes, or until golden brown on the edges. Let cool.
Prepare Espresso Swirl: Dissolve espresso powder in hot water, then stir in powdered sugar.
Drizzle Espresso: Drizzle the espresso mixture over the cooled cookies.