Can I substitute agar-agar powder for gelatin in no-churn ice cream? I saw that many no-churn ice cream recipes use gelatin to prevent crystalization. Unfortunately, I don't have any gelatin left but a lot of agar-agar powder.  Can I use agar-agar powder instead? And if yes, what is the best way to use it? Because normally I have to bring the mixture to a boil to cook agar-agar powder but I don't want to boil my milk. 

Thanks for your help.
Sure, why not.
350ml of liquid with 0.5g of agar-agar powder.
Just use another 50ml of milk for this 0.5g of agar-agar powder. Before boiling it, mix 0.5g agar-agar powder with around 5 to 15ml of warm water to avoid cobble up and then only boil with the 50ml of milk.