And to add: in spring time many Finns pick a deadly poisonous mushroom (Gyromitra esculenta) and boil it 2x5min to remove the poison and cook it as a delicassy after that. Never heard anyone get poisoned by it.
I'll remember to skip the "mushroom delicacy" when I visit Finland :]
The internet recommends boiling outside to avoid poisonous vapors.
It must taste incredible.
Funny fact is that in Russia it is not considered poisonous. There is a special category of “provisionally edible” or “conditionally edible” mushrooms - those that are poisonous if eaten without preparation