first time i tried this it was very delicious. i doubled the recipe cuz our family is big. and i also changed some measurements. quick question tho is baking soda bicarbonate of soda? because i didnt add that i added baking powder which made it cakey but still chewy :) crunch edges too. what i did was i added 1cup butter and 1 cup margarine, only 1tsp salt, no nuts, and 400g chocolate chips (200 milk, 100g dark, 100g white) and the whole recipe made by hand! no machine but what didnt happen was it did not hold its shape even after i froze it! they came together into one big blob..so with the remaining mixture i put it in sandwich pans and made pan cookies (make sure to line the pans with baking paper because i didnt with my 1st pan and it stuck :) great recipe tho! will make again for sure..