In a clean bowl, place the egg whites and start to whisk it with an electric whisk or a stand mixer until it forms soft peaks.
Gradually and very slowly start adding the sugar as the egg whites are whisking. Keep the mixer on low speed.
Once all the sugar is mixed in properly and dissolved into the egg whites, add the vanilla, sprinkle the corn flour, cream of tartar and salt over the whipped meringue and whisk it once again.
The meringue should look thick and glossy and should hold firm peaks.
Line a baking sheet with a parchment paper.
Scoop out the whipped meringue in the centre of the sheet and start to spread it to give it a circular shape.
Don't flatten it too much.
Bake the meringue in a preheated oven at 230F for 90 minutes.
Let it cool completely before assembling.