In a large punch bowl, prepare an oleo saccharum by muddling the sugar and citrus peels gently for a few minutes every 10 minutes over the course of an hour.
Meanwhile, prepare the hot tea, timing the tea steeping to complete just as the oleo saccharum is ready.
Strain the tea into the punch bowl to melt the oleo into a rich, aromatic syrup.
Add the remaining ingredients except the Champagne to the punch bowl.
Add the Champagne and an ice block just before service.
Garnish with 3 orange wheels and fresh mint sprigs.
*Darjeeling tea: Brew 1 tbsp of loose tea per cup of hot water and let steep for 5 minutes.