Collect together your equipment (see Recipe Notes below) and ingredients.

Preheat oven to Fan Oven 160°C/180°C/350°F/Gas 4 and line your baking trays with baking parchment if necessary.

Put the butter, salt and both of the sugars into a large bowl and using an electric whisk beat until fluffy. This should take 3-4 minutes. 

Add the egg and vanilla extract/paste and continue to whisk until thoroughly mixed.

Add the flour and baking powder to the butter mixture and beat, on a slow speed, until almost entirely incorporated. Alternatively, fold in by hand.

Finally, fold through any additional ingredients of your choice. If you want to make two different types of cookies, divide the dough now – the dough will weigh approximately 560g, so remove 280g into another bowl. You can then add different add-ins to each bowl.

N.B. Hold a few chocolate chunks back before mixing in. I often find the last cookie dough ball to be made has no or very few chocolate chunks in it. If you hold a few back you can simply mix into the final cookie.

Next divide the dough into 25 – 27 x 30g balls of cookie dough or 16 – 18 x 50g balls. I am quite specific how I do this. I line a baking tray with parchment, sit it on the top of the scales and zero the scales. I can then check that each cookie weighs 30g or 50g each. I use a heaped tablespoon measure or a small ice cream scoop for the 30g, and a medium ice cream scoop for the 50g. The more accurate you are, the more consistent your cookies will be when cooked. I don’t worry about 2g here or there but I am quite careful. However, when in a hurry, I eye ball it and they still work out very well! Your choice!

Once you have divided the dough into balls, roll gently into a neater shape (the dough will be very soft at this stage) and then stick on any toppings.

To bake straight away: when you are ready to cook your cookies, place them spread out on a baking sheet – I get 4 – 5 per sheet depending on the size of the baking sheet. 

Baking one tray at a time: bake in a pre-heated oven for either 10 - 12 minutes for the smaller size or 14 – 16 minutes for the larger size. (I cook mine for 11 and 15 minutes.)

Baking two trays at a time: add one minute to the total time to cook. Bake for half this time and then quickly swap the trays over i.e. put the top tray on the lower shelf and the tray from the lower shelf and on the higher shelf and cook for the remaining time.

(So for one tray I cook for 11 and 15 minutes and 2 trays for 6/8 minutes, swap the trays and then another 6/8 minutes = 12 and 16 minutes on total.)  

The cookies are cooked when: they have spread out, are starting to brown on the edges and look ever so slightly underdone. They should still be soft in the middle.

Let them cool on the baking sheet for 10 minutes and then transfer to a cooling rack.

To bake later: cover with cling film and refrigerate until you are ready to cook them. Follow the same instructions as above.

If you want to freeze any, before cooking, now is the time: cover with cling film and place in the freezer. As soon as the dough balls are solid, they can be transferred into labelled freezer bags or containers.