Line a baking tray with parchment or baking paper. Preheat oven to 230F/100C. Measure and set aside 3/4 cup of baking sugar. Add reduced, cooled aquafaba to an ultra-clean, stand mixer bowl (instructions in the recipe post). Alternatively, you can use a large glass bowl and a hand mixer.
Whisk the aquafaba until the liquid becomes foamy.
Add cream of tartar, xanthan gum, corn flour and vanilla.
Whisk again on medium-high speed until mixture becomes thick and creamy, forming soft peaks.
Turn mixer to high speed and begin adding sugar, 1 tablespoon at a time in 30 second intervals. Please note, the sugar should be completely dissolved before adding another tablespoon (test this by dipping your finger into meringue and rubbing two fingers together. If it feels grainy, keep mixing). After all sugar has been added, continue to beat until the vegan meringue reaches stiff peaks. The time in minutes for beating will vary. It's done when you lift the beater from the mixer and the meringue is glossy, remains stiff and doesn't move. DO NOT OVERMIX.
Spoon meringue onto a parchment-lined baking sheet one blob layer at a time. Take a clean spatula and form a round disc, approximately 7-8 inches/17-20 centimeters in diameter. Use the back of a clean spoon or table knife to make some cool designs on the sides and top of the meringue.
Cook for 2 hours. When vegan pavlova is finished baking, turn off oven leaving it inside for at least 3 hours to cool completely. DO NOT OPEN OVEN DOOR. Once cool, remove from oven. Using a stainless steel spatula/turner, slide under pavlova and gently loosen it from the parchment paper. Lift parchment paper with pavlova on it and gently slide vegan pav onto a cake plate. You may use the steel spatula underneath the pavlova to help it gently along.