Preheat & Prep:

• Preheat the oven to 350°F.
• Line two baking sheets with parchment paper or silicone mats.

Mix Dry Ingredients:

• In a medium bowl, whisk together flour, cornstarch, baking soda, and salt. Set aside.

Cream Butter & Sugar:

• In a stand mixer (or large bowl with a hand mixer), beat butter, brown sugar, and granulated sugar until light and fluffy.
• Add the egg and vanilla extract, mixing until combined.

Combine & Fold:

• Gradually add the flour mixture to the wet ingredients, mixing until just combined.
• Stir in white chocolate chips and chopped pistachios until evenly distributed.

Shape & Bake:

• Roll two heaping tablespoons of dough into a ball. Tear the ball in half and place the torn side down on the baking sheet.
• Stack the second half on top, leaving about 2 inches for spreading.
• Bake for 12 minutes, or until the edges are lightly browned. The centers may look underbaked but will set while cooling.

Cool & Serve:

• Let cookies rest on the baking sheet for 10 minutes, then transfer to a wire rack to cool completely.