How to cook
Peel the onion and cut it into small pieces and set it aside.
Remove the truffle from the jar and very finely chop it. Set aside the liquid from the jar. You'll need it for the sauce.
Put the butter and olive oil in a pan. Wait for it to melt and add the onion. Fry well for a few minutes. When it starts to change color, add the truffle and the liquid from the jar, that we set aside.
Wait 1-2 minutes and pour the wine. When the alcohol evaporates, add the cream, salt and black pepper. Reduce the heat to medium and let it boil for five minutes.
Turn off the stove and serve the truffle sauce.
*If you wish, you can blend the sauce with a blender.