In the bowl of a stand mixer, combine the gelatin envelopes and 1/2 cup of cold water. Whisk briefly until combined, then let set while you make the syrup mixture.

Meanwhile, in a medium saucepan on medium heat, combine the granulated sugar, corn syrup, salt, and remaining 1/2 cup water together, stirring until combined. Raise the heat to high and cook until the syrup mixture reaches 240 degrees F on a candy thermometer. Remove from the heat immediately.

Turn the mixer on low speed with the whisk attachment and very slowly and carefully pour in the hot sugar syrup a little at a time into the gelatin mixture. Once all the hot sugar syrup has been added, raise the mixer speed to high speed and whip until the mixture is very thick, glossy, and has stiff peaks, about 10-15 minutes depending on the speed of your mixer. Add in the vanilla bean paste and whip briefly to combine.

Liberally dust a 9x13" rectangular baking pan with confectioners sugar - don't be shy! Dust some of the sugar on the sides of the pan as well. Pour the marshmallows mixture evenly into the prepared pan and smooth out into an even layer. Dust the top of the marshmallows with more confectioners' sugar. Let set UNCOVERED overnight to dry out some until you can touch it with your finger and your finger won't be a sticky mess :)

Cut the marshmallow into equal-size pieces with a warm knife or pizza cutter. You can cut the marshmallows as large as you'd like, but mine were medium-size and I got about 30-40.