200g butter at room temperature
250g light brown sugar
2 eggs yolks
275g plain flour
150g chocolate chips
1 tsp baking powder
1/2 tsp vanilla extract
100g of other cookie fillings such as nuts, pieces of fudge or toffee, marshmallows etc
1. Heat oven 180c / 160c fan, put butter and sugar into a large mixing bowl, beat until combined, stir in egg yolks and vanilla, add flour, baking powder, chocolate chips and any other filling you want, mix until a crumbly dough forms.
2. Lightly butter a 25cm ovenproof frying pan, spoon in and flatten the cookie mixture. For a gooey cookie bake for 20 minutes, leave to rest for 5 minutes, scoop straight from the pan and serve with ice cream.
3. For a firmer cookie you can cut, bake for 30 minutes then leave to cool completely before cutting into wedges.