For the risotto with truffles, first sauté the onion and garlic in butter. Add the truffle risotto, bay leaf and thyme, season with a little salt and the white pepper and sauté over medium heat for 2 minutes. Deglaze with white wine. Add the mushroom broth little by little.
When the rice is cooked (after about 12 minutes of cooking), stir in the mascarpone and a few drops of lemon. Season everything again to taste and serve immediately.
If necessary, garnish the risotto with truffles with a few slices of truffle.