Butter

Butter is a Human condiment made from cream or milk, used in many foods.

The crew assigned to the day shift on Deep Space 9 in 2373 enjoyed a short stack of pancakes, dripping with butter, with a side of sausage and pineapple for their breakfast. 

Mashed potatoes with butter was a favored dish of Samantha Wildman, who introduced it to Kes. Kes ate six bowls of it when she underwent premature elogium as a result of space-dwelling lifeforms in 2371. Neelix tasted it and pronounced it "awful," although this was because Kes had added a container of Nitrogenated soil to the recipe, as her body was lacking certain minerals present in soil at that time. 

When Tom Paris recreated the Palace Theater on the holodeck in 2377, he replicated some popcorn for his date with B'Elanna Torres. Later when the crew was invited to a showing of Attack of the Lobster People, Neelix would stand by the entrance, offering popcorn to people as they enter "buttered" or "unbuttered".