Use dark chocolate.
Get 3 mars bars, 3 cups of rice krispies, 3 oz butter. Cut mars bars up, melt them with the butter. When its all melted, bung in the rice krispies. Mix it wellllllll.
Dump the whole lot onto a baking tray, flatten it out so its even. Melt some dark chocolate (you'll need a few big bars of the really nice bitter stuff) and pour that all over.
Leave to cool for a few hours. Cut into squares and use to taunt family with.
Thats a treat thats not too sweet and also not too messy. Take you about 30 minutes if you have everything to hand and you're in a hurry.
And I typoed earlier, I meant cookies, not cookes, lol.