Here are some suggestions but of course there may be plenty of other possibilities:

Very usual (at the restaurant, for example):

C’était très bon, merci.
Tout s’est bien passé, merci.

Common, but more familiar:

Je me suis régalé !
Un vrai festin !

If it was really a great meal and you want to show it, you can add Mes compliments au chef, or Je reviendrais avec grand plaisir after one of those expressions.