Preheat the oven to 180 °C. Grease a baking sheet and line with baking paper.Beat the butter and sugars with an electric mixer until creamy. Add the eggs and vanilla, beating until blended.
Combine the flour, bicarbonate of soda and salt in a bowl. Gradually add to the butter mixture, beating until just blended. Fold in the chocolate chips until evenly spread.Put spoonfuls on the lined baking sheet and bake in batches for 8-12 minutes. Remove from the oven and cool on a wire rack.