OK, this isn't my favourite meal, but is my favourite dish served at a restaurant:
It's from 10 Steak & Sushi, a funky sushi and steakhouse in Providence, RI ... every hour on the hour, bubbles come up from behind the bar; your waiter gives you 3D glasses to look at the pictures in the dessert menu; etc. Very funky. But, at the same time, very expensive and sophisticated.
Anyway, the dish I love there is Death-by-Butter Mashed Potatoes. OMG. To die for (almost literally, I'm afraid). I've been there in groups of three or four, and we've still not been able to finish them! It's a volcanic looking mound of mashed potatoes (more smashed than mashed, really), dripping in pools of butter. Then there's grated cheese on top, and the whole thing is broiled and bubbling and heavenly.