Slice the ripe strawberries into small pieces and place them in a mixing bowl. Add the zest of one lemon and a generous amount of granulated sugar. Stir and let sit for about 6 hours.

Strain the mixture through a fine mesh sieve or cheesecloth into a clean bowl or measuring cup, discarding the solids to collect the syrup.

Pour the golden balsamic vinegar into the syrup and stir well to combine, adjusting the tartness as needed.

Fill a tall glass with ice cubes, pour the shrub syrup over the ice, then top with plain seltzer.

Garnish with additional fresh strawberries and a slice of lemon on the rim. Add a sprig of mint or basil if desired.