1. Preheat the oven to 180°C/350°F/gas 4 and line a large baking sheet with parchment paper.
2. In a pestle & mortar grind together the salt and the lime zest before stirring in the sugar, chilli powder and smoked paprika.
3. Stir through the egg white until it forms a paste.
4. Mix the paste with the nuts and spread evenly in one layer on the baking sheet.
5. Roast in the oven until golden for about 20 minutes. A few mins before they are ready quickly squeeze over the lime juice and then return to the oven for the last few mins of cooking time.
6. Allow to cool on the tray before storing in an air tight container for upto a week – if they last that long!