ooooh.. oooh, I KNOW this one!!
My Dad and Granddad and Uncle all served in WWII. All of 'em came back with 'aquired tastes' in military cusine. All of 'em actually liked spam. However, only my Dad liked powdered eggs and powdered milk.
Sunday breakfasts were sometimes "WWII" breakfasts, including fried spam, powdered eggs, and powdered milk.
Your answer is powdered milk.. it's 'milk' spelled (and made) backwards.
Is skuzzy gonna lick my milk mustache now?