Step 1: Cream the butter and sugar: In a large mixing bowl, cream together the softened butter and confectioners' sugar using an electric mixer on medium speed for 3-4 minutes, until the mixture is light, fluffy, and pale in color. This step is crucial for achieving the proper texture. Beat in the coconut extract until fully incorporated, about 30 seconds.
Step 2: Combine dry ingredients: In a separate bowl, whisk together the flour, cornstarch, and salt. This ensures even distribution of the salt throughout the dough.
Step 3: Mix the dough & fold in nuts: Gradually add the flour mixture to the butter mixture, mixing on low speed just until the dough comes together. Don't overmix – stop as soon as you no longer see dry flour. Gently fold in the chopped macadamia nuts until evenly distributed throughout the dough.
Step 4: Shape the dough & chill: Shape the dough into a 2-inch diameter log wrapped in plastic wrap for slice-and-bake cookies. Or form the dough into a disc and wrap in plastic wrap for the dough to be rolled with a rolling pin and cut with cookie cutters. Refrigerate for at least 60 minutes to help cookies hold their shape.
Step 5: Slice the cookies & bake: Preheat the oven to 325°F (163°C). Line two baking sheets with parchment paper. Using a sharp knife, slice the chilled log into ¼-inch thick rounds. If the dough cracks while slicing, let it soften at room temperature for 5 minutes. Place the cookies on the prepared baking sheets, spacing them about 1 inch apart. Bake for 12-16 minutes, until the edges are just set and lightly golden. The centers should still look slightly underbaked.
Step 6: Cool completely: Let the cookies cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely. They are very delicate when still hot.
Step 8: Chocolate dip or drizzle: Place chocolate chips in a microwave-safe bowl and microwave in 30-second intervals, stirring between each interval, until smooth and melted. If the chocolate is too thick, add 1 teaspoon of a neutral oil such as canola oil to the chocolate. Alternatively, melt in a double boiler. Dip one side of the cookie in melted chocolate, allowing excess to drip off, or drizzle chocolate over cookies using a piping bag. Place on parchment to set. *Optional: sprinkle a little bit of chopped macadamia, shredded coconut flakes, or sprinkles on top of the chocolate before it sets.