Prepare a 8”x8” or 9”x9” pan by lightly greasing it with some butter or oil. Make a parchment paper sling by placing two pieces of parchment paper over each other in opposite directions. Sprinkle a layer of powdered sugar “dust” over the parchment and sides of the pan. Set the pan aside.

In a small bowl, combine the gelatin and 1/2 cup of cold water. Set aside.

In a medium sized saucepan, combine the granulated sugar, corn syrup, 1/2 cup water, and the salt. Bring to the stovetop and stir gently to moisten the sugar entirely. Cook without stirring until the temperature reaches 238 F to 240 F.

To the bowl of a stand mixer with a whisk attachment, add the gelatin puck. Slowly stream in the sugar syrup while mixing on low speed. Once all the sugar syrup has been added, raise the speed of the mixer to medium speed and continue mixing until light, fluffy, and thick. (About ten minutes.) Add the vanilla bean paste and mix until combined.

Pour the marshmallow fluff into the pan and spread it into place. 

In a bowl, combine the powdered sugar and cornstarch.

Using a fine mesh sieve, sprinkle the powdered sugar “dust” all over the surface and allow it to set for a few hours. Cover the top of the pan with a dish towel to prevent the marshmallow from drying out.

Once the marshmallows are set, remove them from the pan and place onto a surface dusted with the powdered sugar mixture. Using a large greased knife, cut the marshmallow square into even strips. Cut each strip into even squares, dusting the cut edges as you go to prevent sticking. 

Store the marshmallows in an airtight container for up to three weeks.