Mix the butter and sugar together using an electric whisk on medium for a few minutes until the mixture becomes pale. Add in the egg and vanilla extract and beat until combined.
Sift in the flour, baking soda and salt and mix until just incorporated. Add in the chocolate pieces/ chips and mix in with a wooden spoon/ spatula.
Cover the bowl with some cling film and place into the fridge for at least an hour or freezer for 30 mins (this will make sure the cookies don’t spread out too much when baking, leaving them overnight in the fridge would be best).
Roll the cookie dough into small balls around 1 inch in size, gently flatten and place onto a baking tray lined with parchment paper.
Place the cookies into the pre-heated oven for 15 minutes.
Once they come out of the oven Allow hem to cool before tucking in; they should be chewy and delicious!