Pour ½ cup cold water into the bowl of a mixer and sprinkle gelatin over top to soften. It is helpful to use a stand mixer as these need to be whipped about 12-15 minutes.
In a small saucepan combine the remaining ½ cup water, honey and salt. Place over medium high heat, clipping a candy thermometer onto the side of the pan and continue to cook until the mixture reaches 240°F, approximately 7 to 8 minutes. Once the mixture reaches this temperature, immediately remove from the heat.
Using a whisk attachment, turn the mixer on low speed and, while running, slowly pour the honey syrup down the side of the bowl into the gelatin mixture. Once you have added all of the syrup, increase the speed to high. Continue to whip until the mixture becomes very thick and is lukewarm, approximately 12 to 15 minutes. Add the vanilla, 1 cup pistachios and 1 cup cranberries during the last minute of whipping.
While the mixture is whipping, prepare a 9x13 pan by lightly oiling a piece of parchment paper and placing it the pan making sure that it covers the sides as well. Sprinkle a light layer of pistachios and cranberries on the bottom of the pan, keeping some for the top too.
When ready, pour the mixture into the prepared pan, using a lightly oiled spatula to spread evenly into pan. Top with remaining cranberries and pistachios. Allow the marshmallows to sit uncovered at least 4 hours, or overnight.