Peel and dice your peaches and add them to a blender or food processor with the water and raspberries (you can also add some sugar here at this point if you want to sweeten it).
Blend until you have a puree and strain the mixture through a mesh strainer to catch the larger bits of peach (you can use a rubber spatula to help push it through).
Add 2 tablespoons of peach puree to a glass and fill with chilled sparkling wine.
Notes
Instead of all peach puree or juice, try switching out half the peach for orange or mango juice for a fruity twist on the classic.