Add the lemon, teabags, and granulated sugar to a big, heatproof jug.
Heat up 2 pints of water, either in a kettle or on the stovetop, until boiling. Pour the water into the jug, and allow the teabags and lemons to infuse for 10 minutes.
Remove them, allow the liquid to cool completely, then place it into the fridge to chill for at least 1 hour before serving with ice cubes, more lemon, and fresh mint.