Preheat your oven to 350°F (180°C). Grease and flour an 8- or 9-inch round cake pan.
Peel and core both apples. Dice one apple into small cubes and slice the other into thin wedges. Toss the cubed apple with 1 tablespoon of sugar and set aside.
In a large bowl, beat the eggs with a pinch of salt until light and frothy.
Add the vanilla sugar and granulated sugar. Continue whisking until the mixture becomes pale and creamy.
Pour in the vegetable oil and warm milk, mixing gently to combine.
In a separate bowl, mix together the flour and baking powder. Gradually fold the dry ingredients into the wet mixture to form a smooth batter.
Stir in the cubed, sugared apples and raisins.
Pour the batter into the prepared pan. Arrange the thin apple slices on top in a circular or fanned pattern.
Bake for 40–45 minutes, or until a toothpick inserted in the center comes out clean and the top is golden.
Allow the cake to cool in the pan for 10 minutes, then transfer to a wire rack to cool completely before slicing.