Line the bottom of the tin with one sheet of edible wafer paper. Keep the second sheet nearby for the top.

Preheat the oven to 160°C/320°F. Spread the almonds and hazelnuts over a baking tray and roast for 10–12 minutes, stirring once, until lightly golden and fragrant.

Transfer the hazelnuts to a clean tea towel and rub away most of the loose skins. Return all the nuts to the oven and reduce the temperature to 90°C/195°F so they remain warm.

Place the honey in a small heavy-based saucepan. Heat gently until it reaches 120°C/248°F. Remove it from the heat and pour it into a warmed heatproof jug.

Place the sugar and water in a second clean saucepan. Heat gently until the sugar has dissolved. Stop stirring and continue cooking until the syrup reaches 150°C/302°F.

When the sugar syrup reaches approximately 135°C/275°F, begin beating the egg white with the cream of tartar and salt. Beat to medium peaks.

With the mixer running on a low speed, slowly pour the hot honey into the egg white. Avoid pouring it directly onto the whisk.

Immediately pour in the hot sugar syrup in a thin, steady stream. Increase the mixer to medium-high and beat for 3–4 minutes, until the mixture is thick, pale and glossy.

Remove the warm nuts from the oven. Working quickly, fold them into the nougat mixture with a sturdy spatula.

Scrape the mixture into the prepared tin and press it firmly into the corners. Place the second sheet of wafer paper on top.

Cover with baking parchment and place a second tin or small chopping board on top. Weigh it down with two food tins for approximately one hour.

Remove the weights and leave the turrón to set at room temperature for at least eight hours, preferably overnight.

Lift it from the tin and cut it into small bars or break it into irregular pieces.