Preheat oven to 350°F and line baking pans with parchment. Beat the butter, brown sugar, and granulated sugar with an electric stand mixer on medium speed for 1 minute.
You can alternatively mix this by hand in a bowl with a wooden spoon. ¾ cup unsalted butter, 1 cup brown sugar, half cup white sugar.
Mix in the whole egg, egg yolk, and vanilla extract. 1 large egg, 1 large yolk, 1 tsp vanilla Mix flour, baking soda, and salt on low speed until just incorporated, scraping sides as needed.
2-cup all-purpose flour, ¾ tsp baking soda, ½ tsp salt Mix in the white chocolate chips briefly.
1/2 cups white chocolate chips Roll handfuls of mixture into balls. Adjust the dough amount per cookie based on desired size.
Lay cookie dough balls on baking pans with room between them for spreading. Bake for 11-13 minutes until edges are brown.
Optional: push more chocolate chips into warm cookies immediately for extra decoration. Transfer the warm cookies to a wire rack to cool after 15 minutes on the baking pans with a spatula.