Beat the eggs with the sugar, oil, flour with baking powder, cinnamon, vanilla. Stir until you get a smooth cake batter.
Peel the apples and dice them finely. Add them to the batter.
Pour it into a greased and floured tray and even it out. Bake in a preheated 356°F (180 °C) oven for 35 min.
Take it out and once it cools, sprinkle with powdered sugar. Cut it into squares and serve!