To a small bowl, add the sugar and lemon zest and massage the zest into the sugar until the zest is evenly incorporated throughout the sugar. 

To a small saucepan, add the diced strawberries, zest and sugar mixture, lemon juice, and still water. Cook over medium low heat and simmer for 10-15 minutes until the strawberries have softened and broken down.

Strain the cooked syrup to remove the strawberry solids, using a spatula or spoon to extract as much liquid as possible.

Stir or whisk in the vanilla bean paste, and move the to refrigerator to cool.

Once cooled, add anywhere from 2-4 tablespoons of the syrup to an ice-filled glass, and top with sparkling water.