Wild Mushroom Risotto

• 1/2 at a time
• 1/4 at the end
• 1,900 gr casserole over moderate hea onion
• 1,200 ml broth
• 180 gr arborio rice
• 120 ml dry wine (white)
• 65 gr mushrooms stems removed (white)
• 60 gr mascarpone cheese
• 40 gr butter (unsalted)
• 40 gr shiitake mushrooms