In a large bowl, combine the simple syrup and the Aperol, stirring well until combined. Store in the refrigerator in an airtight container for up to three months.
In a mixing glass filled with ice, combine the Aperol syrup with six ounces of the prosecco (reserving the remaining six ounces); stir well to combine.
Using a shave ice machine or a food processor, finely crush 4 cups worth of fresh ice. Divide the crushed ice between two large tumblers.
Drizzle half of the Aperol syrup and prosecco combination over the crushed ice in each tumbler.
Divide the remaining six ounces of the prosecco between the two tumblers.
Squeeze one orange twist over each shave ice to express the oils, then drop into the glass. Serve with a straw.