In the bowl of your stand mixer add the 3 packs of unflavored gelatin and ½ cup water, whisk to combine. Stir in the cocoa powder and whiskey. Set aside.

In a heavy duty, medium saucepan over medium heat combine the remaining 1/2 cup water and 2 cups of sugar.

Attach the candy thermometer to the interior of the pan and cook the sugar syrup until it reaches 240°F. and remove from the heat.

Fit your stand mixer with the whisk attachment and start mixing the chocolate gelatin mix on low.

Very slowly and carefully pour in the sugar syrup, with the mixer running, trying to aim towards the center of the bowl. You want to avoid pouring the sugar down the sides of the mixing bowl.

Once all the sugar syrup has been added, increase the speed to medium high and whip for about 10-15 minutes or until you have stiff, glossy peaks. In the last minute, whip in the vanilla extract.

Prepare a 9X9 square baking pan by dusting it with 2 tablespoons of cocoa powder mixed with 2 teaspoons of cornstarch.

Pour the marshmallow into the prepared baking pan, smooth the top and just the top with remaining cocoa powder mix.

Cover with plastic wrap and let sit for at least 6 hours or overnight to set. You know the marshmallows are set when you press on them and it springs back at you.

Flip over the pan to remove the marshmallow square and cut into your desired size using a pizza wheel or kitchen shears.

Toss in some cocoa powder to keep the marshmallows from sticking and store in an airtight container for about 1 week.