Fresh wild mushrooms should be used for this recipe -- cepes or boletus edlulis. Arborio rice has plump, golden brown grains with a nutty flavor. Melt half the butter in a large, heavy pan and saute the onion over a low heat until soft and transparent but not brown. Clean the mushrooms and slice them thinly. Add these to the pan and stir well. Pour in the wine and continue cooking until almost completely evaporated. Add the rice and continue cooking until it begins to change color, then add 1/2 cup of the stock. Cook until the stock has been absorbed by the rice, then add another 1/2 cup stock. Continue in this manner until all the stock has been absorbed. This process will take about 20 minutes, and by the end the rice will be perfectly tender, each grain separate. Add the rest of the butter and the cheese, stir well, cover the pan and leave the risotto to settle for 2 or 3 minutes before serving. Serve with a bowl of additional grated Parmesan cheese. Serves 6. pasta 48