The tricholome de la Saint-Georges or mousseron vrai or mousseron de printemps is a much appreciated field mushroom that pops up around 23 April—St George’s Day. It especially likes the limestone grasslands of the south of France; it’s fleshy and bumpy looking, and tastes good just sautéed in butter.
If you see something similar with a ring or mini veil around the stem, avoid it like the plague; it’s probably a highly poisonous Amanita verna.
Image by User:Strobilomyces