Preheat oven to 350F/180C. Rub the bottom and the sides of a 9-inch round cake pan and line it with parchment paper.
In a large bowl, beat the eggs and sugar together until the sugar is dissolved and the mixture is foamy.
Add the almond flour, cinnamon and lemon zest and fold them in gently to make sure you don't remove the air from the mixture.
Pour the mixture into the prepared pan and bake at 350F for 30-35 minutes or until a toothpick inserted in the middle comes out clean.
Take the cake out of the oven and set it on a cooling rack. Give it a good 10 to 15 minutes to cool down before you attempt to take it out of the pan. Once it's ready, go ahead and sprinkle some powdered sugar over the top.
