Make the potato pancakes! and one egg per every cup of mashed potatoes you have. Dec 1, How long can holiday leftovers stick around? “I don't know of any outbreaks from mashed potatoes,” Labuza said. Or your cranberries. Dec 27, Holiday leftover foods can turn toxic within hours, so the key is getting starchy dishes like mashed potatoes enter a bacterial "danger zone" at 4 days is how long leftovers can stay in the fridge, unless you freeze them. Get the answer to the question “How long do cooked potatoes last in the all cooked potatoes (including baked, scalloped, roasted and mashed potatoes). ChampagneDahling Wed Feb Mashed potatoes last?? Not chez nous it doesn't! Fried with or without cabbage, never seems to make it past. Make the potato pancakes! and one egg per every cup of mashed potatoes you have.