Zest the lemons with a fine grater or microplane. Cut those lemons in half and juice them for 80 grams of juice.
Also add the champagne, the corn starch, the potato starch and the sugar. Mix it well and then while stirring bring this to a boil. Then once thickened pour it into a bowl and keep it in your fridge for later.
The soufflé
Take some soft butter and brush the inside of the glass or ramekins with a thin layer. Start at the bottom and brush to the top.
Add a tablespoon of fine sugar and turn the glass or ramekins to cover the inside. Remove any excess sugar and set it aside for later.
Then transfer the soufflé base into a bowl and mix it well. Now pour the egg white into a mixing bowl and start beating it. Once a white foam starts to form add the sugar and beat it for a couple more minutes till the meringue has stiff fluffy peaks.
Add a third of the meringue to the base and fold this together. Then add the remaining meringue and fold this together as well. Try to mix it as little as possible to keep all the air in the mixture.
Now fill a piping bag and fill the glass. Level it and then use your thumb to clean the side. Bake the soufflé at 175 °C for 8 minutes.
