Add the aquafaba, vanilla, and cream of tartar to a large bowl or the bowl of a mixer. 

Use the mixer or a hand mixer to beat the liquid for about 1 minute until it starts to get fluffy. 

Very slowly sprinkle in the sugar a spoonful at a time while the mixer is on. 

Continue to beat for about 10 minutes until a stiff peak is formed. When you lift the beater the fluff should look glossy and hold a stiff peak, even if you jiggle the bowl the peak should stay as is. It may take more or less time depending on your mixer and brand of aquafaba.