Freyonaise

When humans first settled the Stardew Valley they found this mysterious machine sitting there. Thousands of years passed with them never understanding its purpose, until one day a magpie dropped an egg seemingly by accident into the machine. The machine suddenly roared into life, turning this one egg, into a packaged bottle of mayonnaise, a food item that the locals fell hopelessly in love with, though the surrounding settlements decried this "mayonnaise" calling it out as a foul demon food only eaten by reprobates.

Though the villages tried to tame magpies to turn more of their eggs into their much coveted mayonnaise, they failed in their efforts and settled for the lesser chicken eggs. Though even now many Stardew citizens long for the taste of magpie mayonnaise.