I am not a great cook so was dubious about this one, but it's great:
1 pint double cream
1 tin (small) of evaporated milk
2 tablespoon of golden syrup
OR a good gulg of alcohol (I used Malibu, but apparently baileys or a coffee liqueur or limoncello are all good)
Put all into a bowl, whisk until you need to spoon it out (not sure what the correct term would be).
Freeze.
Serve.
It makes quite a large bowlful! I've run a grating of chocolate through mine for the full Bounty with Booze effect. 
My only problem is that DS has had a taste and loved it- don't think there's enough alcohol in a small cornet to be a concern!