Mars bar slice is a treat I remember making with my mum when I was little. We had such fun playing about in the kitchen making treats like these, truffles and chocolate krispie cakes. There was always chocolate involved.
It's funny, as a child I was offered chocolate and sweets regularly. but I didn't eat a lot and a quarter of sweets would last me a week.
I decided not to go down this route with Cooper. He has chocolate occasionally, but never sweets. We never give him a bar or packet of chocolate to work his way through either, it's more a sharing thing and the great thing is although he loves chocolate, especially dark chocolate, he'll often say no to it and isn't desperate for it like some children I see hounding their parents.
I know there's debate about this and some say it causes problems in later life, but I believe the best thing to do with food, any food, but especially unhealthy food, is let children try it but not make a big fuss about it. Making a fuss gives it too much importance and it can become an emotional issue or a power struggle.