- Preheat the oven to 180°C.
- In a large bowl, mix the butter with the white and brown sugars until well-combined.
- Stir in the vanilla and egg until incorporated, then add the flour, bicarb and salt.
- Mix the dough until just combined, then stir in chocolate chunks.
- Scoop out 1 1/2 tablespoons of dough and place about 5cm apart on a prepared baking tray.
- Bake for 7-10 minutes until puffy. They will look underbaked in the middle but will firm up once cooled.
- Cool on the tray for 5 minutes, then transfer to a cooling rack. Once cooled, store in an airtight container.