Line a 9 inch square pan with parchment paper. Liberally grease the parchment paper with softened butter and sprinkle with powdered sugar.
In the bowl of a stand mixer fitted with a whisk attachment, add the 56g (¼ cup) of water and sprinkle the gelatin on top in an even layer. Set aside to bloom.
In a small saucepan, combine the other 56g (¼ cup) of water, granulated sugar, light corn syrup, and salt.
Heat the saucepan over medium heat, stirring frequently until the sugar dissolves.
Raise the heat to medium-high, and without stirring, bring it to 240 degrees F.
While the mixer is on low speed, slowly drizzle the hot sugar over the gelatin.
Once all of the hot sugar is poured in, increase the mixer speed to high and mix until thick and cool (about 100 degrees F). Add the vanilla paste while it is mixing.
Pour the marshmallow mixture into the prepared square pan and spread into an even layer.
Tap the pan on the counter a few times to release any air bubbles.
Allow to set at room temperature for at least four hours or overnight.
Once set, turn the marshmallows out onto a surface dusted with powdered sugar. Sprinkle more powdered sugar on top, then cut marshmallows into 1 inch squares, and toss in a bowl of powdered sugar.
Enjoy!