|My homemade rhubarb fool/posset/syllabub/panna cotta|
Syllabub "an English sweet dish....made of milk or cream, curdled by wine/cider or other acid, and often sweetened and flavoured" Wikipedia definition of Syllabub
Posset "was a British hot drink of milk curdled with wine or ale" hang on, haven't I just typed that? "The word "posset" is mostly used nowadays for a cold set dessert loosely based on the drink, containing cream and lemon, similar to syllabub." Wikipedia definition of Posset
Fool "an English dessert...folding pureed stewed fruit into sweet custard. Modern fool recipes often skip the tradidional custard and use whipped cream" Wikipedia definition of Fruit Fool
Panna Cotta "is an Italian dessert made by simmering together cream, milk and sugar, mixing this with gelatin, and letting it cool until set" Wikipedia definition of Panna Cotta
As you can see, I was essentially right(ish).
So next time you're in a restaurant pondering over the syllabub, posset, fool and panna cotta - just be aware that they're all interchangeable and amount to the same thing.