01 -
Sift together the all-purpose flour, baking soda, and salt into a bowl.
02 -
Using an electric mixer, cream the unsalted butter for 2 to 3 minutes until fluffy and pale yellow.
03 -
Scrape down the bowl sides, then add granulated and brown sugars. Beat for 1 to 2 minutes until smooth. Add the egg and vanilla extract, mixing on low speed until combined.
04 -
Gradually add the flour mixture at low speed, mixing just until incorporated. Fold in the semi-sweet chocolate chunks and white chocolate chips evenly.
05 -
Place parchment, wax paper, or plastic wrap on a work surface. Scoop dough and form into two logs approximately 5 cm in diameter. Wrap tightly and refrigerate at least 2 hours, up to one week.
06 -
Preheat oven to 175°C and line a baking sheet with parchment paper.
07 -
Using a serrated knife, slice logs into 0.6 to 0.8 cm thick rounds. Place cookies about 2.5 cm apart on the prepared baking sheet.
08 -
Bake for 10 to 12 minutes, until edges turn golden brown. Remove from oven and transfer cookies to cooling racks. Repeat with remaining dough as needed.