Melt butter and chocolate: In microwave-safe bowl, combine melted butter and 50g dark chocolate. Microwave in 20-second intervals, stirring between, until smooth. Set aside.
Mix wet: In large bowl, beat together brown sugar, granulated sugar, egg, and vanilla until combined. Add melted butter-chocolate mixture and mix until smooth and glossy.
Mix dry: In separate bowl, whisk together flour, cocoa powder, baking soda, and salt.
Combine: Add dry ingredients to wet. Mix with spatula until just combined. Do not overmix.
Add chocolate chips/chunks: Fold in 80g dark chocolate chunks and 80g milk chocolate chunks.
Triple chocolate: if you want to make triple chocolate cookie add 50g of white chocolate chunks/chips.
Check consistency: If dough is too soft, refrigerate 1 hour. If too hard, add dash of milk.
Portion: Scoop dough into 50g balls (about 3 tablespoons each). Place on parchment-lined tray.
Preheat and prep: Preheat oven to 175°C (350°F). Line baking sheet with parchment.
Bake: Place dough balls on prepared sheet, 2 inches apart. Bake 11-13 minutes until edges set and slightly crackly, centers still soft.
Cool: Let cookies rest on baking sheet 5-10 minutes. Transfer to wire rack.
Serve: Enjoy warm or at room temperature.
