Butter

Butter is churned cream of milk. An unctuous (usually) yellow solid fat, often spread on bread or used in the production of cakes, biscuits and pastries.

Praising pure butter and denouncing oleomargarine; Puck magazine cartoon by Opper, March 31, 1880

Until recently farmers denounced oleomargarine as an inferior chemical substitute for butter. It is actually just as nutritious, and a lot cheaper.