Place 1/2 cup of water in the bottom of a stand mixer fitted with the paddle attachment. Sprinkle the gelatin over the top. Set aside.
Combine the remaining 1/2 cup water with the honey in a medium pot fitted with a candy thermometer. Stir often for the first 1-2 minutes, then cook undisturbed until the mixture reaches 240ºF. (This will likely take 10-15 minutes.) Remove from heat.
Turn the mixer on low to break up the gelatin. With the mixer on low speed, slowly pour in the honey mixture. Once added, gradually increase the speed to high and beat until the mixture has increased in volume significantly and resembles marshmallow fluff, 8-10 minutes.
While the mixture is beating, whisk to combine the powdered sugar and arrowroot starch in a bowl. Line an 8x8-inch baking dish with parchment paper, leaving a 1-inch overhang on all sides. Dust the parchment paper with powdered sugar mixture by sifting it over the top with a strainer. Transfer the beaten marshmallow fluff to the baking dish, spreading it out evenly with a spatula. Dust the top with powdered sugar mixture. Set aside at room temperature for at least 5 hours.
Remove the marshmallow “slab” from the pan using the parchment paper. Cut into squares with a sharp knife, dusting the knife and marshmallows with powdered sugar mixture as needed/desired. Marshmallows are best eaten within 1 day.