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.