Step 1

Add all ingredients to a shaker filled with ice and shake until well-chilled.

Step 2

Strain into a rocks glass over ice.

Step 3

Squeeze the orange peel (peel side facing the glass) over the cocktail to release its oils and rub on the rim of the glass. Drop the peel into the glass and add the lemongrass stalk as a garnish.

Step 4

Cut the lemongrass stalk into 2-inch pieces, and use the back of the knife to crush each of the pieces.

Step 5

Add the lemongrass and water to a small saucepan and bring to a boil over high heat. Reduce heat to low and simmer for 5 minutes.

Step 6

Remove from heat and stir in the sugar until fully dissolved. Let cool completely and strain. The syrup can be made ahead and will keep in the fridge for up to 2 weeks.