Heat butter in a medium-sized saucepan over high heat.
Caramelize the onion. Add the pancetta and cook for 2-3 minutes untill it gets a nice golden color.
Reduce heat to medium. Add the mushrooms and rice. Cook for 1-2 minutes.
Pour the wine and scrape the bottom of the pan with a wooden spoon.
Pour 1 liter of warm water. Season with salt and pepper. Add the bay leaf.
Cover with the lid and simmer for about 20 minutes.
Add the prunes and pine nuts. Bring heat to high and stir constantly untill rice absorbs all of the remaing water.
Once the rice starts to stick at the bottom of the pan remove from heat and set aside.
Optional Step: At this point, you may add the cream.
Let rice stand for about 10 minutes to release its steam.
Transfer rice to your preferred mold, and push gently with a big spoon. Let rice stand in the mold for 2-3 minutes. Unmold on a large plate.
Serve with extra prunes and pine nuts on top.