Warm 6 heatproof mugs with hot water. For the batter, separate 2 eggs and beat the yolks in a bowl.
Stir 2 tablespoons of superfine sugar, 15ml of overproof aged rum, 1 pinch of ground cinnamon, 1 pinch of ground cloves, and 1 pinch of ground nutmeg into the yolks.
Whisk the whites until stiff and fold them into the yolk mixture.
Empty the mugs. Divide 270ml of cognac and 90ml of aged rum among them, add 2 tablespoons of batter to each, and stir well. Top up with 540ml of boiling water, dividing it evenly.
