In a large bowl, cream softened butter, brown sugar, and white sugar until light and fluffy.
Add the egg, extra yolk, and vanilla extract. Mix until smooth.
In another bowl, whisk together flour, baking soda, baking powder, and salt. Gradually fold into wet mixture.
Stir in chocolate chips. Chill the dough for 30 minutes for thicker cookies.
Preheat oven to 180°C. Scoop ~40 g dough balls onto a lined baking sheet. Bake 10–12 minutes until edges are golden.
Cool 5 minutes on the tray, then transfer to a wire rack. Serve warm or store airtight.
