Preheat the oven to 260F. Pour the egg whites into the bowl, add cream of tartar and start whisking until foam appears on the surface.
Add powdered sugar and continue beating until fluffy and strong peaks. Gently add cornstarch and mix everything until combined.
Transfer the meringue to a piping bag fitted with a star nozzle.
Pour the meringue onto a silicone mat, making the bottom first and then 2-3 turns for the walls of the cake.
Leave space between the cakes as they will expand a little while baking.
Put in a hot oven and bake for 10 minutes at 260F and another half an hour at 180F. Let cool in the oven for 20 minutes with the door ajar.
Pour the whipping cream into a bowl, add the powdered sugar and vanilla.
Whip the cream until fluffy on high speed. It is important not to overwhip the cream. Whipping time depends on the power of the mixer - it is about 2-4 minutes.
Transfer the whipped cream to a piping bag fitted with a star nozzle.
Fill Pavlova cakes with whipped cream, top with lemon curd. You can buy this at your local grocer or make it homemade.
Decorate the cakes as desired - fresh berries, mint, almond flakes, powdered sugar or syrup. Serve immediately.