In the bowl of a stand mixer (or a large mixing bowl if using a hand mixer), add 1/2 cup cold water. Sprinkle the gelatin over the water and let it sit for 5-10 minutes to bloom.
In a medium saucepan, combine 1/2 cup water, marshmallow root, honey, and maple syrup. Bring to a light boil, stirring until combined, then stop stirring and attach a candy thermometer. Cook until the mixture reaches 225-240° F, about 7-10 minutes. Remove from heat immediately.
With the mixer on low, slowly pour the hot syrup into the bloomed gelatin, aiming for the side of the bowl to avoid splashing. Gradually increase the mixer speed to high and whip for 8-12 minutes, until the mixture is thick and holds soft peaks. Should resemble the look of the "Fluff" in the store.
Line an 8x8-inch baking pan with parchment paper and dust with arrowroot powder. Pour the marshmallow mixture into the pan, smoothing the top with a spatula. Sprinkle another layer of arrowroot powder on top. Let sit covered at room temperature for 4-6 hours (or overnight) to set.
Once set, lift the marshmallow slab out using the parchment paper. Dust a knife or pizza cutter with arrowroot powder and cut into squares. Toss each marshmallow in additional powder to prevent sticking. Shake any excess off, if needed. Store in an airtight container at room temperature for up to 2 weeks.
