Cookies with Gooey Marshmallow Dip

Name: Cookies with Gooey Marshmallow Dip
Ingredients: Serves 8; For the cookies:; 150 grams butter, melted; 125 grams light brown sugar; 100 grams caster sugar; 2 teaspoons vanilla extract; 1 egg & 1 yolk; 300 grams plain flour; 1/2 teaspoon bicarbonate of soda; 150 grams chocolate chip cookies; For the dip:; 300 grams Milk Chocolate Chips30 Large Marshmallows