Add the mint and honey to a heat-safe container, like a canning jar.
20 grams fresh mint leaves, 80 grams honey
Pour the hot water over the mint, then stir to fully dissolve the honey. Set aside to cool completely, about an hour in a cool place. Some time is needed for the mint to steep, so even if you can cool it more rapidly, leave it for at least half an hour before straining.
150 ml boiling or very hot water
Strain the syrup through a fine mesh sieve. Squeeze out the mint leaves to release any liquid. Add the lemon juice and stir to combine. This is the syrup base.
2 large lemons, juice only
The syrup can be refrigerated in a sealed container at this point and used as you'd like. To serve in a pitcher, add the syrup to a large pitcher or bottle and top with the remaining water (add more or less water* to your taste, this will adjust the sweetness). Serve with ice, lemon slices, and mint sprigs or leaves.
1 litre still or sparkling water
For individual glasses, use syrup to your taste and top with water. I use about two tablespoons of syrup for a glass but that is not very sweet.
Notes
* Use 750 ml (3 cups) for a sweeter, more typical lemonade taste. I find this amount makes too-sweet a drink but adjust to your taste.