In a large, deep frying pan, heat the oil and fry the sliced zucchine and their flowers for about 5 minutes until tender. Add the rice and stir it around until coated with oil, heated through and shining. Season with salt and pepper, then begin adding the hot stock, stirring continuously. Add a ladleful at a time and wait for the rice to absorb it before adding any more liquid. This will take about 20 minutes. When the risotto is creamy and velvety but the rice is firm to the bite, remove from the heat. Season generously with salt and pepper, stir in the butter and cheese. Cover and leave to rest for 2 minutes. Transfer to a warmed platter and serve immediately.