Add the cherry liqueur to the bottom of two chilled coupe glasses (or champagne flutes).
In the glass of a Boston shaker, add the fresh-squeezed mandarin orange juice and powdered sugar. Stir to mix until dissolved.
Add the gin and ice to the shaker glass. Cover with the metal half of the shaker, and shake until combined and very cold, about 15 seconds. Pour through a hawthorne strainer into the prepared glasses.
Top with the prosecco and then garnish with cocktail cherries to serve.
Notes
Cherry liqueur: There are different types of cherry liqueurs, and for this recipe I recommend using one that has a balance of sweet and tart. If you can't find the liqueur, replace with cherry syrup or grenadine and add a couple dashes of cherry bitters instead.
Make ahead tip: This drink is very fast to mix and serve, and it taste best when prepared just before enjoying. You can multiply the ingredients to make more at once, if you have a large enough shaker. I recommend a Boston-style shaker if baking large batches at once.