In a saucepan combine the honey and water, bring to a simmer and stir until the honey is combined with the water. Add the pear slices, lemon peel and sprig of rosemary. Simmer until the pears are soft and easily mashable, and the liquid has reduced a little bit - about 15 minutes. Cool a bit abd puree in a food processor or a blender, put in fridge until completely cold.

To make the cocktail, spoon two tablespoons of the puree into a champagne flute, and top with prosecco. Garnish with pear slices and a sprig of rosemary.