Combine the water, sugar, strawberries and basil in a medium saucepan over medium high heat. Let the sugar dissolve and the flavors from the strawberries and basil infuse the syrup for about 10 minutes.

Remove the saucepan from the heat and let cool to room temperature.

Once the mixture has cooled, strain out the liquid into a container and discard the strawberries and basil.

In a cocktail glass, combine the vodka, strawberry basil syrup, champagne or prosecco and a squeeze of lemon juice. Stir to combine and serve immediately.