Step 1

Dust the bottom of an 8"x 8" pan with powdered sugar and set aside.

Step 2

Put the aquafaba in a mixing bowl with the cream of tartar and mix on high for 6 minutes until very fluffy.

Step 3

Add some vanilla extract and whip for 3 more minutes until it is white again and it forms very stiff peaks. (You need to whip the aquafaba for a total of at least 9 minutes.)

Step 4

In a small saucepan, combine water and agar agar and bring to a boil.

Step 5

Boil the water and agar agar for 3 minutes stirring frequently.

Step 6

Add sugar and boil for another 3 minutes stirring constantly over medium-low heat. (Be careful not to cook it too hot or you will burn or caramelize the sugar.)

Step 7

Turn off the heat and add the hot sugar mixture into the beaten aquafaba.

Step 8

Add this mixture slowly while beating aquafaba with a mixer set to low for about 30 seconds.  This will turn the fluffy white mixture a little shiny.

Step 9

Quickly pour it into the pan that has been dusted with powdered sugar.

Step 10

Dust the top of the marshmallows with powdered sugar and let sit and cool for at least an hour.

Step 11

Cut into 1" squares and dust all sides with powdered sugar.

Step 12

Turn your oven to 150°F (66°C).  Once it reaches that temperature, turn it off and set your cubed marshmallows in the warm oven for about an hour to dry out a little.