Preheat the oven to 170°C.

In a microwave safe bowl, melt the butter in 20 second blasts in the microwave until runny.

Add your sugars, salt and vanilla to the bowl and mix until incorporated.

Add in the egg and mix until incorporated.

Sift in the flour and stir until just combined.

Add in 100g of the white chocolate and stir until just combined.

Chill in the fridge for half an hour.

On a greaseproof paper lined baking tray, dollop the cookie mixture evenly and leaving enough space for the cookies to spread. put 3-5 chunks of white chocolate onto the top of the cookie dollops to give the shop bought effect when they're cooked.

Put in the oven for 11 minutes, they should be quite squishy when they come out.

Leave to cool, as the cookies cool, they will firm up and form a soft and chewy texture.