The marshmallows can be made in an 8”x8” or 9”x9” square baking dish or pan. Coat the bottom and sides of the dish liberally with oil. In a small bowl, whisk the confectioners sugar and cornstarch, then liberally coat the oiled dish with this mixture as you would flour a pan. Also coat a rubber spatula and set aside for later.
In the bowl of a stand mixer, bloom the gelatin by dissolving it in ½ cup of the water. Slowly sprinkle all of the gelatin over 1/3 cup of water. Set aside.
In a small food processor, pulverize the freeze-dried raspberries to a powder. Sift the powder through a fine mesh sieve into a bowl and discard the seeds left behind. Stir 2-3 tablespoons of the raspberry powder into the remaining confectioners sugar-cornstarch mixture. Set aside.
In a small saucepan, combine the sugar, corn syrup, and remaining ¼ cup water over medium high heat. Bring to a boil and continue to boil for about one minute.
Begin to whip the gelatin using the whisk attachment on the stand mixer on high speed. Slowly pour the hot syrup into the gelatin along the side of the bowl. Add the salt, raspberry flavoring, rose water, and vanilla. Add pink food coloring a few drops at a time until you get the color you want (I used just a few drops of red to get light pink). Continue whisking on high, until the marshmallow forms stiff peaks, about 5 minutes.
Working quickly, use the oil-coated spatula to scrape the marshmallow into the prepared pan. Smooth the top and sift a light layer of raspberry sugar over top. Let the marshmallow set up for at least one hour.
Place a sheet of parchment on a cutting board or work surface. Turn the marshmallow out of the pan onto the parchment, then place the remaining raspberry sugar in the baking pan, to provide a wide surface (with sides) to dust the cut marshmallows.
Brush a large, sharp knife with oil and keep a wet paper towel or cloth handy. Cut the marshmallows into squares, wiping and re-oiling the knife frequently.
Toss the marshmallows in the raspberry sugar, coating all sides well and knocking off any excess.
Eat them up! Store the marshmallows in a Ziploc bag or other airtight container. They’ll keep for a couple of weeks. The coating may hydrate a bit overtime and get a flecked pink look to them. Very pretty!