Prepare a cake pan: Line a 9x9 cake pan with plastic wrap and coconut oil to prevent sticking.
Bloom the gelatin: In your stand mixer, add the gelatin and ½ cup of cold water. Whisk to combine and let it sit while you make the sugar syrup.
Make the sugar syrup
In a medium-sized saucepan over medium heat, add the remaining ⅔ cup of water.
Add the xylitol and the allulose to a saucepan. Bring the mixture to a boil. Using a candy thermometer, bring the sugar syrup to 240°F.
Make the marshmallows in your stand mixer
Mix on low: Turn the mixer on low and break up the gelatin mixture. Sometimes I use a spatula for this step. You want to get the gelatin off the sides of the mixer and broken up so the sugar syrup can melt it evenly. Try to do this a few minutes before the sugar syrup reaches full temperature on the stovetop.
Add the sugar syrup: With the mixer still on low, slowly add the hot sugar syrup. Mix on low and slowly begin increasing the speed as the mixture cools slightly. Continue to mix for approximately 3 to 5 minutes.
Mix on high: Once the mixture is well combined and starts to get a little bit fluffy, turn the mixture on high. Beat for about 8 minutes.
Add the salt and vanilla: You can use another flavoring here such as strawberry, lemon, or peppermint. You can also add a few drops of food coloring for colored marshmallows.
Continue to mix on high: Mix for another 3 to 4 minutes. The mixture will be very sticky.
Prepare the marshmallow to set
Scrape: Scrape the mixture into your prepared cake pan. It's a good idea to oil your spatula to help with all of the stickiness.
Cure: Let the marshmallows sit for 5 to 6 hours before cutting.
Cut The Marshmallows
Cut: Turn the marshmallows out and cut with an oiled knife into 25 pieces.
RECIPE TIPS
Make-ahead: Marshmallows will last 4-5 days at room temperature in a tightly covered container.Flavor variations: You can create different flavors by adding that flavor between steps #5 & #6. (For example, try 1/2 tsp cinnamon, lemon oil, orange oil, OR 1/4 tsp peppermint extract.) Food coloring can also be added if desired.