In a small saucepan over medium heat combine the water, sugar and hibiscus leaves. Stirring until sugar dissolves, bring to a boil then remove from heat and cool. Strain into a jar to remove all the hibiscus leaves. Chill syrup completely until ready to use.
To make the cocktails
In large collins glasses pour one and a half ounces of hibiscus syrup and a couple mint leaves in each glass and muddle just to bruise the mint leaves. Add about 2 tablespoons of crushed ice then a lime wheel on top of the ice. Layer more ice, mint leaves and lime wheels until the glasses are full of ice. Combine the spiced rum, white cranberry juice and lime juice in a cocktail shaker with ice. Shake well then divide amongst the glasses and top with soda water. Garnish with a lime slice, a sprig of mint and whole cranberries. Serve immediately
Notes
if you can’t find white cranberry juice you can use white grape juice or regular cranberry juice. If you use regular cranberry juice you will have an all red drink and not get the layered effect as seen in these cocktails. It will still taste just as good though. To make the simple syrup with tea bags instead of loose leaf hibiscus flowers, heat the water to boiling and steep 4 hibiscus tea bags (make sure its 100% hibiscus leaf or as close to it as possible) for 6 minutes in the pan, until its very dark red. Remove the tea bags and add the sugar then bring to a simmer and stir until the sugar is dissolved. Transfer to a container with a lid, like a mason jar, and chill until ready to use.