Place the peaches and raspberries in a blender, and blend on the purée setting for 1 minute, until throughly mixed.

Then I quickly strained the fruit puree to remove any raspberry seeds. This step is optional.

Combine the purée and the prosecco in a pitcher, or mix individual cocktails by adding 3 tablespoons of the purée to each glass of prosecco.

Add some extra frozen peaches to garnish, and to help keep the drink cold. I didn't use raspberries because they break up and I don't like the seeds in my cocktails.