The Russula cyanoxantha or russule charbonnière is a fairly common European mushroom, with a charcoal or violet or even blue or green coloured cap. It grows in the forest from summer to early autumn.
Russule bleu et jaune, charbonnier, colombine verte are among its other names in French.
Other prized edible russoles include the russula vesca or russule comestible (bare-toothed russula or flirt), with a mild nutty flavour.
Images by archenzoderivative work: Ak ccm, Luridiformis at English Wikipedia, MediAtta, Paffka