In a medium bowl, add the strawberries, along with the sugar, pinch of salt, pepper and balsamic vinegar. Allow the strawberries to sit for 10 to 15 minutes. To a blender, add the strawberries and all their juices. Pulse until the mixture resembles a puree. Give it a taste and adjust the sugar accordingly. Run the mixture through a sieve, discarding the seeds and pulp. You should end up with a scant 1/2 cup.

To assemble the cocktail, divide the basil leaves between glasses. Muddle the basil leaves, being sure to press the stems, with a muddler (or you can use the back of a wooden spoon). Fill all the glasses with ice cubes. Pour in 1 to 2 ounces of gin, 2 to 3 tablespoons of strawberry mixture and top with tonic. Give the mixture a good stir and garnish with basil flowers and a few turns of freshly ground pepper.