- Preheat the oven to 350°F/180°C. 
- In a large bowl, whisk together the caster sugar, salt, and butter until a paste has formed with no lumps. 
- Whisk in the egg and vanilla, then add the peanut butter and beating until light ribbons fall off the whisk. 
- Sift in the flour and baking soda, then fold the mixture with a spatula, being careful not to overmix too much. This will cause the gluten in the flour to toughen which will result in cakier cookies. 
- Fold in the chocolate chips evenly. 
- Shape into balls and Then chill the dough for at least 30 minutes. For a more intense flavor and deeper color, chill the dough overnight. The longer the dough rests, the more complex its flavor will be. 
- Put the cookie balls on a parchment paper-lined baking sheet, leaving at least 4 inches of space between cookies and 2 inches of space from the edges of the pan so that the cookies can spread evenly. 
- Bake for 12-15 minutes, or until the edges have started to barely brown. 
- Leave it to cool then enjoy.