Prepare a 9x13 baking dish lined with parchment paper.
In the bowl of a stand mixer, add ½ cup cold water. Sprinkle the gelatin evenly over it and let it sit for 10 minutes. In a saucepan, combine remaining ½ cup water, maple syrup and salt. Cook on medium heat for 6-8 minutes.
Turn the stand mixer on low and carefully pour the hot syrup into the bloomed gelatin. Gradually increase to high speed and whip for 8–10 minutes until mixture is thick, fluffy, and tripled in volume. Add vanilla extract at the last minute.
Pour mixture into a prepared baking dish lined with parchment paper. Put in the fridge for 1-2 hours to expedite the process.
Lift marshmallows out with parchment. Cut into squares with a sharp knife or kitchen scissors. You can toss pieces in arrowroot powder to prevent sticking if you want.