Is there any dessert that needs a knife? A friend of mine told me that there is no dessert that needs a knife to eat. I'm sure that this is not true, but I can't find a good example in the Internet. So is there any dessert that needs a knife to eat? And if yes, what kind of dessert?
In certain cultures whole pieces of fruit, like an apple, for example, will be served for dessert and the diners are expected to eat it using fork and knife only - no fingers. as far as traditional desserts such as pies and cakes, I'm sure you must mean whether the individual serving requires a knife because, of course, a whole cake or pie must be cut into individual servings. I've only seen dessert forks offered for traditional baked desserts.  There's an interesting website on manners that deals specifically with eating desserts using a fork and spoon, but no knife.

http://www.etiquettescholar.com/dining_etiquette/table_manners/dinner_etiquette/desserts/desserts.html