1. In a small bowl, combine the strawberries and sugar, toss well. Let sit for 15 minutes.
2. In a cocktail shaker, combine the basil and strawberries and any juice collected in the bowl. Gently crush using a muddler or wooden spoon.
3. Fill the shaker with ice, then add the vodka and lemon juice. Cap the shaker.
4. Shake vigorously. Pour into a large glass, then top with soda water. Stir.
5. Garnish with a strawberry and fresh basil.