In a bowl, beat butter, brown sugar, castor sugar and vanilla extract until the mixture is light and fluffy.
Now add all purpose flour, baking soda and cornflour and mix well until all the ingredients are combined.
If the dough feels dry, add the milk, 1 tablespoon at a time, until you achieve the desired consistency. Refrigerate the cookie dough for 30 minutes.
Preheat the oven to 180 degrees celsius.
Press the chilled dough into a 7-inch cast-iron skillet or round cake pan. Flatten the surface and stud it with chocolate chips and chopped hazelnuts.
Bake for 20 minutes until the edges of the cookies have puffed up. Then, place the Magnum truffle bar on top and dig in!
Recipe by Bake with Shivesh at https://bakewithshivesh.com/pizzokie/