1. Generously line 9x12 pan with parchment paper, leaving extra paper to hang over the sides to make it easy to remove later.
  2. Thoroughly dust the parchment paper with 1/4 cup of arrowroot starch. Save remaining 1/4 cup for later. Make sure arrowroot starch is spread out evenly.
  3. Pour 1/2 cup of water into stand mixer.
  4. Then, sprinkle powdered gelatin evenly over the water. Allow to sit for approximately 5 minutes, or until mixture thickens a bit.
  5. In medium saucepan, combine the agave, vanilla extract and salt.
  6. Cook the mixture on high heat until the solution boils, then reduce to low heat to prevent burning.
  7. Using a candy thermometer, cook mixture until temperature reaches 240⁰F. Be sure to stir the mixture occasionally with a wire whisk. This step, depending on your stove, should take about 5-10 minutes. Hitting 240⁰F here is essential. (This temperature is referred to as "The Soft Ball Stage" and if it does not hit 240⁰F, the marshmallows will be wet and will not form correctly.)
  8. Once you've hit 240⁰F, remove mixture from heat.
  9. Then, with the stand mixer set to low, carefully and slowly pour the heated mixture into the bowl with the gelatin.
  10. Whip the mixture with a wire whisk attachment on medium setting for 2-3 minutes or until the mixture thickens and is fully combined.
  11. Now, set the mixer to high and whip marshmallow mixture until it becomes lighter in color, increases in size, can hold its form for a few seconds and the bottom of the bowl is cool enough to touch. This step may take around 15 minutes. Don't be afraid to over-whip here. You want nice stiff peaks.*
  12. Pour marshmallow mixture onto prepared pan. Use a spatula to scrape sides of bowl and smooth out mixture.
  13. Allow marshmallows to sit and dry out, uncovered. Usually 8 hours or overnight is enough to let them set. If you want to roast them over heat, it is better to allow additional drying time in the refrigerator, about 48-72 hours covered with a cloth.**
  14. Dust with remaining arrowroot starch.
  15. When the marshmallows are dry, remove them from the pan and cut with a pizza cutter or sharp knife into desired sizes and shapes.***
  16. Add more arrowroot starch if they are still sticky.
  17. Enjoy your creation!