Toast the Hazelnuts: Preheat your oven to 180°C (160°C fan). Spread the whole blanched hazelnuts on a baking tray in a single layer. Toast for 8-10 minutes, or until they are lightly golden and fragrant. Give the tray a shake halfway through to ensure they toast evenly. Let them cool completely. Select 20-24 of the best-looking nuts for the centres and finely chop the rest.

Prepare the Wafer and Filling: Place the wafer biscuits in a plastic bag and gently crush them with a rolling pin until you have a coarse crumb texture. You don't want a fine powder. In a medium bowl, combine the chocolate hazelnut spread, cocoa powder, and about two-thirds of the crushed wafers. Mix until well combined.

Shape the Truffle Centres: Line a small baking tray with baking parchment. Take about a tablespoon of the hazelnut mixture and flatten it in your palm. Place one whole toasted hazelnut in the centre and carefully roll the mixture around it to form a neat ball. Place the ball on the prepared tray. Repeat with the remaining mixture and hazelnuts.

Chill for Firmness: Place the tray of truffle centres into the freezer for 20-30 minutes. This step is crucial as it makes them firm enough to handle during the dipping stage and prevents them from melting into the warm chocolate.

Prepare the Coating: While the centres are chilling, prepare the outer layer. In a microwave-safe bowl, combine the chopped milk and dark chocolate. Microwave in 30-second bursts, stirring in between, until the chocolate is almost fully melted. Stir until smooth. If the chocolate seems too thick, stir in the teaspoon of oil. Now, stir in the remaining crushed wafers and the chopped toasted hazelnuts.

Dip and Coat: Remove the chilled truffle centres from the freezer. Working one at a time, drop a ball into the melted chocolate mixture. What works best for me is using two forks to roll it around until it's fully coated, then lifting it out and letting any excess chocolate drip off.

Final Set: Place the coated truffle back onto the parchment-lined tray. Repeat with all the centres. If the chocolate coating starts to thicken too much, you can gently reheat it in the microwave for 10-15 seconds.

Chill to Perfection: Place the finished truffles in the fridge for at least 30 minutes, or until the chocolate shell is completely firm and set. Once set, they are ready to be enjoyed!