Add the brine from your drained chickpea tin into a small pot on medium-high heat and boil until it has reduced. It should reduce to just about under 3/4 cup of liquid.
Remove from heat and let it cool in a jar or bowl in the fridge. While this is cooling, make and cook your base following the instructions below.
In a stand mixer bowl, or using a hand mixer, add cooled chickpea brine to the bowl and whisk with a whisk attachment. Gradually increase the speed of the whisk until high and the brine has turned white with soft peak starting to form.
Add sugar and cornstarch together in a bowl and mix. Gradually add a tablespoon of this mixture at a time until finished and the mixture has turned into glossy and stiff peaks. Add vanilla and mix for a further few seconds to incorporate this.
You will know when you have reached stiff peaks when you can hold your meringue bowl upside down the meringue does not drip or fall out.