Pre-heat the oven at 180 degC and start to prepare the molds, with baking paper at the bottom of the molds. You can cut normal baking paper in circles with the size of the mold.
With a stand mixer at medium speed , beat the eggs, vanilla extract, and lemon zest. Add the sugar in 3 portions, giving it time to incorporate. Beat for 8 to 10 minutes. The mixture should triple its volume.
Using a rubber spatula, fold gently a small portion of corn starch into the egg mixture. Repeat until you incorporate all the corn starch. Check that there is no remaining corn starch at the bottom of the bowl.
Divide the mixture into the two molds and bake for 20-25 minutes approx. at 180 deg°C, with preheated oven.