- STEP 1
Preheat the oven to 180℃/350ﾟF/Gas mark 4. Lightly grease a 38 x 25-in (15 x 10-in) baking tin.
- STEP 2
Beat the butter and sugar until light and fluffy, about 5 minutes (the secret!). Beat in the vanilla extract.
- STEP 3
Stir in the flour and chocolate chips (or chunks). Pat the dough into the prepared baking tray.
- STEP 4
Bake for 25-28 minutes, until the edges are slightly crispy. Allow to cool before slicing into squares. Enjoy!