Preheat the oven to 170 C / Gas 3. Line two baking trays with baking parchment.
In a mixing bowl cream together the butter and sugars.
In a separate bowl, beat together the egg and vanilla extract then gradually add to the butter and sugar, beating continuously.
Sift in the flour, bicarb and salt and mix until just combined (take care not to overmix). Add the chocolate chips to the mixture with a cutting motion. Put a tablespoon of the mixture on the prepared baking tray for each cookie, allowing room to spread.
Bake in the preheated oven for 10 to 15 minutes until golden brown. Remove from the oven and serve warm or allow to cool before enjoying.