Preheat the oven to 350°. Spread the hazelnuts in a pie plate and bake for about 12 minutes, or until the nuts are fragrant and the skins blister. Let cool, then transfer the nuts to a kitchen towel and rub to remove the skins. Transfer the nuts to a food processor and pulse until finely ground. Transfer the nuts to a bowl and wipe out the food processor.
In the food processor, combine the ricotta, goat cheese, mustard and truffle oil and process until smooth and creamy, scraping down the sides of the bowl. Transfer the dip to a serving bowl and stir in the hazelnuts. Season with salt and white pepper, add a little more truffle oil, if needed, and serve.
The dip can be refrigerated overnight.
Pear and apple slices, garlic or black pepper crackers, flatbreads and grissini.