Cut in two pieces the bigger of the mushrooms. In a large pan heat the oil with the butter and saute for 5'-6' all the mushrooms and the dry onions. Add the garlic and the fresh onions and continue sauteing for 5', stirring frequently. Add the wine and and season.
Cook the mushrooms on medium heat until most of the liquid has been absorbed. At the end, add the parsley and the blue cheese and stir well before serve.