In a small bowl mix gelatin and ¼ cup of cold water. Set aside.

In a pot, over medium/low heat, dissolve the granulated sugar with 1 ½ cups of cold water. Once dissolved, add the gelatin. Stir to incorporate

Turn the heat up to medium/high and let the sugar/gelatin mixture come to a low boil. (Be careful that the mixture does not boil over. This happens quickly, so you will want to keep an eye on your pot and lower the heat as necessary.)

Let the sugar/gelatin mixture gently boil for 10-15 minutes. Set the mixture aside and let it cool slightly.

Very carefully, pour the sugar/gelatin mixture into the bowl of a stand mixer, fitted with the whisk attachment. Add vanilla extract.

Begin to mix on low speed (work carefully as the sugar mixture will still be very hot), after 30 seconds increase to medium speed, and finally to high speed after an additional 30 seconds.

Continue mixing on the highest setting for five minutes, or until the sugar/gelatin mixture has come to a thick glossy white consistency that forms soft peaks. (If your mixture is still a little “runny”, continue to let the mixer run for a few minutes.)

Meanwhile, prepare a 9x13 baking dish by spraying all four sides with non-stick baking spray. Then, place a piece of parchment paper inside the pan with the paper extending past the dish. (I like to make sure the “sides” of my parchment paper extend well past my pan to give “handles” that I can use to help release the marshmallow). Use additional spray over the parchment paper, as well as a little on the "handles".

evenly sprinkle about a 1/4 cup of powdered sugar on the bottom of the pan (over the parchment paper)

Working quickly, pour marshmallow mixture evenly in the pan. Ensure that the marshmallow reaches all four corners. Sprinkle the remaining powdered sugar on top of the marshmallow making sure the entire marshmallow is well covered. Fold the edges of the parchment paper over the sprinkled marshmallow and set in your fridge.

Allow the marshmallow to set for 8-12 hours or overnight.

Once marshmallow has set, remove from the fridge and unfold the parchment paper. Using the parchment paper as handles, lift the marshmallow out of the pan and place on a cutting board.

Use a clean knife to cut 1 inch cubes out of the marshmallows (or a cookie cutter). If your knife becomes sticky, be sure to clean it off with warm water (a clean knife will create smoother edges)

Enjoy.