ok here it is
250g plain flour
1/2 teaspoon bicarbonate of soda
1/2 teaspoon salt
170g unsalted butter, melted
200g dark brown soft sugar
100g caster sugar
1 tablespoon vanilla extract
1 egg
1 egg yolk
I use 3 - 50g mars bars but you can use choc chips (about 325g or anything you fancy)
pre-heat over to 170 /gas mark 3
Cream together the melted butter, brown sugar and caster sugar.
Mix the egg, egg yolk and vanilla extract until light and creamy
Sift the flout bicarb and salt together then add to the butter sugar egg (etc) mix. Mix until all blended together.
Add mars bar
Then line your baking tray with grease proof paper add dollops of cookie dough (I find one big desert spoon is plenty) but would suggest putting one dollop in each corner and one in the middle as they do spread out a LOT (you might need to do two loads in the oven) and cook for about 15 mins. After 15 mins if u touch the cookie it will be VERY soft but it will harden once taken out the oven you just need to check that the edges are firmer than the middle and should be fairly firm (don't sink in like when u touch the middle)
Take out and leave to cool you will have the BEST chewy cookies ever.