Preheat the oven: Set your oven to 180°C (350°F). Grease and line a 24 cm (9-inch) round cake pan with parchment paper.
Prepare the apples: Peel, core, and thinly slice the apples (as thin as possible — almost translucent). Set aside.
Make the batter: In a large bowl, whisk together the eggs and sugar until slightly frothy.
Add the milk, vanilla extract, cinnamon, nutmeg, baking powder, and salt. Mix well to combine.
Gradually sift in the flour, whisking until you get a smooth, thin batter.
Combine apples and batter: Add the sliced apples to the bowl and gently stir until every piece is well coated with batter. The mixture should look mostly apples with just enough batter to hold them together.
Bake the cake: Pour the apple mixture into the prepared pan, smoothing it out evenly.
Bake for 35–40 minutes, or until the top is golden brown and a toothpick inserted in the center comes out clean.
Cool and serve: Let the cake cool in the pan for about 10 minutes, then transfer to a wire rack to cool completely.
Dust with a little cinnamon or powdered sugar before serving, if desired.