The phrase "to cover the potatoes" means to put something like a lid or a cloth on top of the potatoes so that they are completely hidden or protected.
Sentences with «to cover the potatoes»
Cover the potatoes with water in a pot; season with salt, cover and boil until just tender, 2 minutes. (pearltrees.com)
The caramel is salty, and then there's these clusters of chocolate covered potato chip. (housegoeshome.com)
While the beef cooks, cover the potatoes in water and bring to a simmer. (fedandfit.com)