In a medium saucepan combine 2 cups water, lemon verbena leaves, chopped lemongrass, and crushed sugar. If using candy for extra nostalgic aroma, add it now. Bring the mixture to a gentle simmer over medium heat, stirring to dissolve the sugar. Reduce heat and simmer gently for 8–10 minutes to extract the herbal and sweet notes.

After simmering, remove the pan from heat and stir in the vanilla extract and yellow food coloring (start with 1 tsp; add more if you want a brighter color). Cover and let the syrup steep for 20–30 minutes to deepen flavor.

Strain the syrup through a fine-mesh sieve or cheesecloth into a heatproof bowl or pitcher, pressing the solids to extract as much liquid as possible. Discard solids. Let the syrup cool to room temperature, then refrigerate until cold (about 1 hour). The final syrup yield will be roughly 1 1/2 to 2 cups.

Carbonation & Serving

Mix and serve

To assemble, add 1 part chilled syrup to 3 parts chilled sparkling water (for example, 1/2 cup syrup to 1 1/2 cups sparkling water) into a pitcher or individual glasses with ice. Stir gently to combine. Taste and adjust sweetness by adding more syrup if desired.

Pour into glasses over ice, garnish with a lime wedge if using, and serve immediately. Keeps refrigerated (syrup only) for up to 1 week; do not carbonate the syrup directly—always mix with chilled sparkling water at service.