For the shrub:
Rinse raspberris and place them in a quart size mason jar.
Fill the jar to the top with white vinegar, put the lid on, give the jar a little shake and place it in the refrigerator for 10 days. Give the jar a little shake once or twice a day.
After 10 days, strain the raspberry vinegar through a mesh strainer lined with cheesecloth. Squeeze the cheesecloth as needed to get all of the vinegar out of the berries.
Measure the raspberry vinegar and pour into a medium saucepan. Add 1-1/2 C. white sugar per 2 C of raspberry vinegar, turn the heat on to medium and bring to a boil, stirring as needed to dissolve the sugar.
Once the sugar is dissolved and the mixture starts to boil, remove from heat, let cool and transfer to a glass bottle. Store the raspberry shrub in the refrigerator until ready to use.
For the cocktail:
Add 1-1/2 oz gin and 1 oz raspberry shrub to a rocks glass
Fill glass with ice, top with sparkling water and squeeze in the juice from a lemon wedge. Stir and garnish with a few raspberries before enjoying.