Although Ramsay did not actually specify what his favorite dish is, he has confessed that he has a sweet tooth. He says that he can actually eat anything sweet for breakfast, lunch, and dinner. It is likely that if you would like to impress the chef, it is best that you would serve something nice and sweet.
Of course, if you try to defend your dish and it isn’t good, except that you are going to get a barrage of insults. Try your best to just go with the flow and just cook the best dessert possible for one of the most famous chefs in the world.