Another experiment with aquafaba. Turned out well, although they became quite sticky after a day, need to dry them out at room temperature for longer. Quite satisfying making your own marshmallows without gelatin. You'll need a kitchen thermometer. This is adapted from Seitan Is My Motor.

For dusting:
1/2 c cornflour
1/2 c icing sugar

1/2 c toasted desiccated coconut

For the marshmallows:
1/2 c  water plus 1/4 c water
2 tsp agar powder
3/4 c sugar
1/3 c glucose syrup
1/2 c aquafaba (brine from can of chickpeas)
1/2 tsp xanthan or guar gum
1/2 tsp lemon juice
1 tsp vanilla extract
red food colouring if desired

Line a 20cm square baking tin with baking paper and dust the bottome liberally with the cornflour/icing sugar mix.
In a small saucepan dissolve the agar and 1/2 c water.
In another small saucepan bring to boil the sugar, syrup and 1/4 c water. Put in your candy thermometer. Boil for 6 minutes until the mixture reaches 120C.
Bring the agar mixture to a boil, cook for 1 min then take off the heat to cool.
While the sugar is boiling whisk up the aquafaba, xanthan gum and lemon juice in a large bowl for about 2 min using an electric hand beater or stand mixer. Add in vanilla then beat until stiff. Pour the hot sugar syrup into the aquafaba mixture while beating. The mixture will continue to thicken.
Add the agar mixture and continue to beat for 5 min or until the bowl has cooled down.
Transfer to your baking tin and spread out evenly with a spatula. At this stage I put in a few drops of red food colouring and swirled it around with a knife to achieve pinky swirls in the marshmallow. Dust the top well.and leave to set at room temperature for at least 2 hours.
Then remove from the tin and cut into your desired shapes and dust with further cornflour/icing sugar.
I made a cutter with a little plastic capsule bottle. And I rolled half in toasted coconut.
Leave to dry for 24 hours until dry on the outside. Then keep in an airtight container.