In a stand mixer with whisk attachment, add 1/2 cup of water and gelatin. Allow to bloom.
Using a medium pot, affix a candy thermometer to the side of the pot. Place pot on medium to medium high heat. Add remaining water, coconut sugar and salt. Mix until combined and then stir continuously until the consistency of the mixture is a soft taffy and the candy thermometer reads "soft ball," about 4-6 minutes.
Turn mixer on medium and slowly add sugar mixture to incorporate with the gelatin. Turn stand mixer up to medium high and let mix until sugar mixture turns a golden creamy color and becomes fluffy, about 8-10 minutes,
While marshmallows are mixing, grease a 9x9 glass or metal cake pan and line with parchment paper, leaving end to hang of the pan. Flour lightly with arrowroot powder..
Turn off mixer and - working quickly - spread the marshmallow mixture in the pan as evenly as possible. Sprinkle more arrowroot powder over top. Allow to set up in fridge for about 6 hours or overnight.
Gently lift parchment paper from pan and invert marshmallows over a cutting board. Cut marshmallows to desired size and store in a glass or plastic continer on the counter for up to 2 weeks or in the fridge for up to 1 month.