You will want to have everything prepped and ready to go ahead of time. Once the marshmallows are ready to pour you need to work fast as everything starts to set up quick. Make sure to have whisk attachment ready for your stand mixer or hand mixer as well.
Line an 8"x8" pan with parchment paper ensuring the paper goes up all sides of the pan. Dust with powdered sugar.
In a large bowl (I use my stand mixer) add 1/2 cup of cold water with gelatin. Mix to combine and let sit to bloom.
In a medium saucepan add 1/2 cup cold water, maple syrup and salt. Mix to combine then place over medium heat until the mixture comes to a boil. DO NOT STIR after this point as that will encourage crystallization.
Allow mixture to boil until it reaches 240F-245F, this takes 15-20 minutes so be patient. Keep an eye on the mixture during this time as it can quickly boil over and cause a mess.
Quickly pout the mixture in the same bowl as the gelatin and begin to whisk.
Once everything starts to come together add in your vanilla extract or vanilla beans.
Continue whisking until mixture has tripled in size, the bowl is cool to the touch, and when the whisk is removed the drizzle holds its shape in the bowl.
Quickly pour mixture into prepared pan. You have about 30 seconds before everything sets up too much.
Allow marshmallows to set up completely (about 4 hours).
Remove marshmallows from the pan and sprinkle with additional powdered sugar. This helps your knife from sticking too much when cutting.
Cut marshmallows into desired size with a sharp knife. Dipping each marshmallow in additional powdered sugar to prevent them all from sticking to each other.
Store in an air tight container for up to 2 weeks.