2) Puree the peaches and orange peel in a blender with 375ml of the sugar syrup until smooth. Strain through a fine-meshed strainer into a bowl. Transfer the puree into a pitcher or clear glass bowl.
3) For each serving, pour 2 to 4 tablespoons of the peach puree into a champagne flute. Slowly pour enough Prosecco into the flute to fill. Gently stir to blend. Garnish each with an orange peel twist, and serve.
Do-Ahead Tip: The peach puree can be made one day ahead. Cover and refrigerate.