Place egg whites, maple syrup, and vanilla extract in the bowl of a stand mixer. Beat on high until peaks form when you lift the beater out of the mixture.
While the egg mixture is beating, heat the water and gelatin in a small saucepan over medium heat until the gelatin is completely melted.
With the mixer still going, carefully pour the gelatin mixture into the bowl of the stand mixer. Try to pour it down the inside of the bowl so that it doesn't hit the beater and make a mess. Continue beating on high for 10 minutes.
While the marshmallows finish beating, lightly great a 9x13 glass pan and then dust with coconut flour.
Once 10 minutes is up, spread the mixture in your prepared pan. Allow to set for at least 4 hours or preferably overnight. Use a sharp knife or kitchen scissors to cut the marshmallows into desired shapes and sizes. You can also pipe the marshmallows onto a baking sheet that has been dusted with coconut flour to make fun marshmallow shapes.