2 1/2 cups plain flour
1 tsp salt
1 tsp baking powder
160g unsalted butter, softened
1 cup caster sugar
3/4 cup brown sugar, firmly packed
1/2 tsp vanilla extract
3 cups dark and milk chocolate bits
3/4 cup of walnuts, chopped
Preheat oven to 180C. Line two oven trays with baking paper and set aside.
Combine flour, salt and baking powder in a medium bowl and set aside.
Beat butter in the large bowl of an electric mixer on medium to high speed for 30 seconds. Add both sugars. Beat on medium speed for about 5 minutes or until mixture is light and fluffy, occasionally scraping sides of bowl.
Beat in eggs and vanilla until combined. Beat in as much of the flour mixture as you can with mixer on low speed. Stir in any remaining flour mixture with a wooden spoon until combined. Stir in chocolate bits and walnuts.
Drop dough onto prepared trays in 2-tablespoon portions 4 cm apart. Lightly press down on dough to flatten. Bake 12 minutes (or 14 if dough is chilled) or until edges are lightly brown. Cool cookies on tray for 1 minute. Transfer to wire racks, allow to cool and serve.
To make double chocolate-chip cookies, divide mixture in two. Add 1/4 cup cocoa to one 1/2 and bake as directed. Top with ganache.