My friend made the veganized version of this very usual dish. A comfort food for me and something that I used to eat all the time before being vegan. This version came out delicious and very similar to the non-vegan one, only cruelty and guilt-free.
These are the ingredients: 4-5 potatoes (boiled in their skin and then diced), 1 sliced onion, 4-5 mushrooms finely sliced, the juice of 3 smaller lemons, olive oil, salt, pepper, homemade vegan mayonnaise.
We sliced the mushrooms and marinated them for an hour in the lemon juice and olive oil with some salt. We kept them in the fridge, while the potatoes were boiling and my friend made the mayonnaise.
For the mayonnaise she used corn powder, 4 spoons of boiling water, half of a boiled potato, 3 spoon of mustard, salt, pepper and sunflower seeds oil. She mashed the potato (while the potato is still hot), added the boiling water and then she added the corn powder. Mixed everything and then she added the mustard and the oil, the salt and the pepper. It is a very nice vegan mayonnaise.
At this point all that was left to do was to mix the diced potatoes, the sliced onion, the marinated mushrooms and the mayonnaise and she added a bit more salt and pepper. It was very delicious and comforting.