Measure the butter into a large bowl and microwave for 30-60 seconds or until melted.
160 grams Unsalted butter
Add both sugars, the whole egg, egg yolk and vanilla. Mix to combine.
130 grams Light brown sugar, 90 grams White caster sugar, 1 medium Egg, 1 Egg yolk, 1 teaspoon Vanilla extract
Add the flour, salt and cornflour. Fold to make a thick cookie dough.
280 grams Self-raising flour, 1 teaspoon Salt, 1 teaspoon Cornflour
Fold in 150g of the white chocolate chunks. Reserve the extra 50g to decorate the baked cookies later.
200 grams White chocolate
Cover the bowl with clingfilm and refrigerate for 1 hour.