In a blender, purée the peeled, seeded peach. Set aside.

In a pint glass, hand press 2 thyme sprigs with a muddler. Add 1 ounce of the peach purée, the simple syrup, the Prosecco and the bitters.

Fill the glass with ice. Stir swiftly for 30 seconds.

Strain into a flute. Garnish with the remaining thyme sprig.