Preheat oven to 160°C. Place sugar in a saucepan over medium heat and cook, swirling the pan, for 8 minutes or until a dark caramel colour. Immediately pour into a 1L lightly greased loaf pan. Set aside for 20 minutes to set.
Whisk eggs and extra egg yolks in a bowl until combined. Whisk in remaining ingredients until combined. Strain through a fine sieve, then pour over caramel.
Place in a deep roasting pan and pour in enough boiling water to come halfway up sides. Bake for 40 minutes or until just set with a gentle wobble in the centre. Stand in pan for 20 minutes, before turning out onto a serving dish to cool to room temperature. Refrigerate for at least 1 hour before serving.