Stir the sugar and water together in a pot, bring to the boil, then reduce the heat, add the mint leaves and allow the syrup to simmer for 10 minutes.
Remove from the heat, and allow to cool.
Strain in a fine mesh strainer (or mesh bag) over a bowl and discard the mint leaves.
Pour into a jar or bottle and keep in the fridge for up to 2 weeks.
Notes
When infusing the mint, make sure the mixture is at a simmer and not at a boil. Boiling mint may cause the flavor to become bitter.Let the syrup cool before straining as hot sugar water can burn.If you want a more intense mint flavor, add more mint leaves or let the syrup infuse for a longer time.Always use a sterilized jar or container when pouring the syrup to ensure there is no bacteria growth.If your syrup is too cloudy, a second straining may be necessary.