In a high-speed blender, combine the peach slices, brandy, lemon, and honey. Blend until smooth. The puree will be quite thick, so stop and stir as needed. If it's still too thick, add additional brandy 2 tablespoons at a time until you have a smooth puree.
For each drink, spoon your desired amount of puree into the bottom of a champagne glass (I use about 3 tablespoons). Slowly and carefully top with prosecco (it will foam up quite a bit, so be patient and pour slowly down the side of the glass). With a long-handled spoon or a butter knife, stir gently to combine. Enjoy immediately.
Notes
TO STORE: Leftover puree can be refrigerated in an airtight jar for up to 1 day.