The neat thing about this is, you can play around with the ratio of herbs to suit your own tastes. The herb-infused rum will last a fair old while.
1 big mixed bunch bay leaves, thyme and parsley
1 bottle good-quality aged rum
Per serving
50ml herb rum
20ml basic sugar syrup
20ml lime juice
Freeze the herbs, then crush with a mortar and pestle. Infuse the herbs in the rum for an hour or two, strain and decant into a sterilised jar.
Put the rum, syrup and lime in a cocktail shaker, shake over ice and strain into a chilled glass. Garnish with a thyme sprig or bay leaf.