1. To make the deviled eggs: Boil the eggs in a medium saucepan for 10 minutes.

2. Meanwhile prepare the mayonnaise: Whisk the egg yolk with mustard then pour sunflower oil continuously while whisking, until the mayonnaise is set. Add lemon juice, salt, and cayenne powder.

3. Drain eggs and run under cold water until cool enough to handle. Peel and halve eggs lengthwise; remove yolks and transfer to a bowl, reserving one cooked yolk for garnish. Mash remaining yolks with a fork; mix in mayonnaise and press through a sieve to make smooth.

4. Transfer to a pastry bag fitter with a plain or star tip. Pipe the yolk mixture into egg whites; grate the reserved egg yolk over, then garnish with chopped chives and sprinkle with additional cayenne powder. Serve the spicy deviled eggs immediately, or chill for up to 2 hours.

Note: Instead of piping the filling with a pastry bag and tip, you can use a resealable plastic bag with a corner snipped off. Or just spoon it into the egg whites.