Add the egg whites to your electric mixer bowl and whisk on medium speed (4-6) until it reaches a foamy stage. At this stage, you can add the lemon juice. Continue whipping.
When the egg whites are at soft peak stage, lower the speed to medium-low (3), and add the sugar mixed with the cornstarch, 1 - 2 tablespoon at a time. Scrape down the sides of the bowl at least once while adding the sugar. Do not rush this process. This can take about 10 -15 minutes. Continue whipping.
Once all the sugar is added, increase the speed to medium (4), and whisk the egg whites just until the sugar has completely dissolved, and the egg whites are thick and glossy and hold their shape well.
While your egg whites are in the electric mixer, cover your tray with parchment paper. You can draw the size of the pavlova or just do it without a measurement. We recommend a 9cm circle per pavlova, which is the size of a 1-cup ramekin.
Using a clean spoon, scoop the meringue from the bowl and fill the inside of your drawn circles, or shape a circle freehand. Pile the meringue in the middle of the drawn circle - you should end up with a dome.
After 40-45 minutes, open the oven and check if the pavlovas are hard on the outside. If they are, turn off the oven and open the door just a crack. Leave the pavlovas inside the oven to cool around 30 min.