First, boil a pot of water (say, four chunky mugs worth) and brew some Darjeeling in it. After a few minutes, take out the teabag/ball and add the following,

• a lemon, thinly sliced
• a chunk of ginger, chopped into wee bits
• a stalk of lemongrass, torn up
• a star anise
• one small green chili, split lengthways a couple of times