Peel and cube the peaches, place in a blender and blend until you have a smooth puree. Then pass the puree through a sieve into a clean bowl. (At this point you can chill the puree for a couple of hours if you want).
Pour a third of the puree into 3 medium sized flute glasses and fill to the rim with very cold Prosecco, stir to combine. Top with a peach slice if desired. Serve immediately. Enjoy!
The perfect measurements for a Bellini are 1 part puree and 2 parts Prosecco.