Peel and dice the apples and put in a bowl with lemon juice and sugar.
Beat the eggs with the sugar and grated lemon rind.
Then add, mixing well after each ingredient, the yogurt, the salt, the oil, the flour, the baking powder, the cinnamon, if desired.
Grease and flour a cake pan (approx. 6 cm diam., preferably spring-form type) and pour in the batter. Cover the surface with the apple slices making a concentric pattern.
Bake in a pre-heated oven at 180°C for 40 minutes.
Let cool and dust with powdered sugar.
If you have a sweet tooth serve on a bed of vanilla sauce.
