Why do sleb chefs keep describing food as Unctuous?

[TisPityShesAWhore]

Unctuous:

Pious, smug

Oily, greasy.

What has that got to do with a leek and cheese dish?

It seems to be being used to describe something sort of gooey and delicious. Which Unctuous isn't.

Perhaps they can't cook and it is oily and greasy. Either that or they are thick.

Do they? Ugh, how unappetising!

I would like, though, to see a Valentine's dinner, prepared by a loving husband, be referred to as "uxorious".