My 3yo wanted purple mash potatoes, it didn’t really work because I used yellow potatoes. Then my 3yo decided she didn’t want potatoes so my wife and I were stuck eating prison gruel.
i've worked a significant time of my life in kitchens, never came i across purple mashed potato.
i've seen it in hells kitchen, i guess, and assumed, that they use normal potatos and add some "color"
now i had to search and found purple potatoes. you said your's were yellow. this means your potatoes were partly purple?
sorry, stupid german here.
gonna leave one of my favorite foods here, kinda looks like your mashed potatoes. labskaus:
https://mybestgermanrecipes.com/north-german-labskaus-recipe/