Ideally using a stand mixer with the paddle attachment, mix the butter, caster sugar and light brown soft sugar together until fluffy and paler in colour. This will take 3-5 minutes in an electric mixer (I use speed 3)
Add the egg and vanilla extract and mix in
Add the plain flour, baking powder, bicarbonate of soda and salt and mix them in until just combined. You can put these ingredients in a separate bowl, and mix them together before adding them, if you like
Then mix in the chocolate chips briefly, just to evenly distribute them
Divide the dough into portions, I weighed the dough out to make each cookie an equal size
Roll the dough portions into balls using your hands, place them on either a lined baking tray, or into a tupperware container lined with baking paper. Chill them in the fridge for 30 minutes
Meanwhile, pre-heat your oven to 180C Fan/400F/Gas Mark 6
After the 30 minutes is up and your oven is pre-heated, place the dough balls onto lined baking trays, leaving space (at least 2") between them to spread. If you don't have enough baking trays, keep the dough in the fridge and bake the cookies in batches
Bake for 12 minutes, remove from the oven and leave the cookies to cool for at least 10 minutes on the baking trays before moving to a cooling rack
Enjoy warm, or once fully cooled. Store leftovers in an airtight container and eat within 3-4 days
Video
Notes
Make sure all your ingredients (particularly the butter and egg) are at room temperature before you start baking.
I prefer to use unsalted block style butter for this recipe, and you will get the best results with it.
I highly recommend using the mix of light brown soft sugar and caster sugar for these cookies.
You can use either milk, dark or white chocolate chips or a chopped up chocolate bar for the cookies.
Although I provide cup measurements, I highly recommend weighing your ingredients out using digital kitchen scales. It is the most accurate way to measure ingredients and will ensure the best results. Digital scales are very low cost and can be purchased for around £12 ($16.50) .
For teaspoon (tsp) and tablespoon (tbsp) measurements, please use measuring spoons and not the type of spoons you eat with. Again this will ensure accuracy and provide the best results.