Steps
Preheat the oven to 170°C (340°F) and grease a small cake pan.
Separate the egg whites and beat them with a pinch of salt until stiff peaks form.
In another bowl, whisk the egg yolks with the sugar until creamy.
Fold in the ground almonds, lemon zest, vanilla, and cinnamon into the yolk mixture.
Gently incorporate the egg whites into the batter, being careful not to deflate the mixture.
Pour the batter into the prepared pan and bake for 50-60 minutes, performing a toothpick test to check for doneness.