Preheat oven to 200°c.

Brush eight 150ml soufflé dishes or ramekins with melted butter. Dust with a little extra caster sugar, tapping to remove excess.

Use electric beaters to whisk the egg whites and cream of tartar until soft peaks form. Gradually add the sugar, beating constantly, until the mixture is stiff and glossy.

Meanwhile, gently warm the curd and zest in a saucepan over low heat. Stir in the limoncello, then transfer to a large bowl. Use a large metal spoon to gently fold one-third of the egg whites into the lemon mixture. Continue to fold in the remaining egg white until just combined, taking care not to lose too much volume.

Divide among ramekins and run your finger around the inside edge of each ramekin. Bake for 12 minutes or until golden and risen. Dust with icing sugar, then serve immediately with extra chilled limoncello