This is the recipe just in case you require it:
1.5 oz Campari
1.5 oz sweet vermouth
1.5 oz prosecco
Increase the Campari and sweet vermouth into a mixing glass with ice and stir. Add prosecco and stir all over again, then pressure into a champagne flute. Alternatively, strain into a rocks glass with ice. Garnish with orange peel or slice. Prime with far more prosecco for extra sweetness, to flavor.