I also added a half teaspoon of truffle salt which is definitely one of those foodie ingredients not part of the regular pantry. (strawberriesforsupper.com)
After mashing the potatoes, I just mixed in the spinach, drizzled in some truffle oil, and sprinkled with truffle salt. (confessionsofachocoholic.com)
I added shiitake mushrooms and black truffle salt which gave such a nice rich savoury taste to the broth. (gutsybynature.com)