Marshmallows:

Line an 8×8-inch square tin with parchment in a criss-cross pattern, allowing a 1-inch overhang on all sides. Spray with nonstick spray.

Pour 120 milliliters (1/2 cup) Prosecco into a large mixing bowl (if using a hand mixer), or the bowl of a stand mixer. Sprinkle gelatin evenly over the water. Set aside.

In a large, heavy-bottomed sock pot, stir together granulated sugar, corn syrup, remaining Prosecco, and salt. Bring mixture to a boil and boil, without stirring, until syrup reaches 240° F (116° C) on a candy thermometer.

Carefully pour hot syrup over gelatin. Mix on high speed until thick, pale, and voluminous, about 8-10 minutes.

With an oiled flexible rubber spatula, scrape marshmallow into prepared tin. Loosely cover with a well-oiled sheet of aluminum foil. Allow to set at room temperature until firm, at least 4 hours, or overnight.

Cutting and Coating:

In a small bowl, whisk together cornstarch and confectioner’s sugar. Generously dust a large chopping board with the powder. Turn marshmallow slab out onto dusted surface. Sift top of slab with more powder.

With a sharp, well-oiled chef’s knife, cut marshmallow into squares.

Toss cut marshmallows in additional powder, coating all sides evenly.

Dust or sprinkle with edible glitter. Store in an airtight container or sealed food storage bag at room temperature for up to 1 month. Do not refrigerate.