In a large bowl beat butter with a whisk or electric mixer till smooth and creamy.
Add both the sugars and beat until light and fluffy.
Add vanilla extract and eggs (one at a time). Mix till incorporated.
In another bowl sift in all the dry ingredients. Add walnuts and chopped chocolates and mix well.
Add the dry ingredients to the wet ingredients in 3-4 parts for ease of mixing. Mix with a spatula till well combined.
Make balls from the cookie dough. (Each ball is around 80 g or 4½ tbsp).
Place these balls in a tray and cover with a plastic wrap. Leave in the refrigerator overnight or freeze for at least 30 minutes.
Preheat the oven to 200℃/390℉.
Place the cookie balls onto a parchment/butter paper lined baking tray 1-2 inches apart. Place some chocolate chips on top.
Bake them for 12-15 minutes or until the cookies lose their gloss and appear matte.
Let them cool completely in the tray itself before transferring or serving.