Put the rice, milk, half of the sugar, cinnamon and salt into a heavy-based saucepan and add the grated lemon zest into it.
Preheat the oven to 325F (160C). Butter a 20cm/8in springform pan. You can also use non-stick spray if so desired. Place a piece of parchment on the bottom before closing the sides around the base, trapping the parchment. This will ensure a good seal, and will make it easy to transport the cooked cake off the metal base for serving.
Whisk the egg whites in a clean bowl until stiff, then set aside.
In a separate smaller bowl, add the remaining sugar to the yolks, and whisk until pale and frothy. Add the vanilla and 2 teaspoons of juice from the zested lemon to the yolks and sugar.
Leave the tin on a wire rack for at least one hour. It should be room temperature before you proceed. Slide a sharp knife around the outside of the cake to release it from the metal sides, and unclip the tin. Using the parchment paper lift the cake gently off the metal base and transfer it to a cutting board. From here you can gently lift the cake to a cake stand or serving plate before decorating.
You can make the cake the day before you want to serve it. Just cover loosely with plastic wrap or some other sealed container. Make sure it is cooled before you do this.
See blog post for more details and serving suggestions.