Step 2

In a large bowl, beat the eggs with the sugar until the mixture has tripled in volume and is pale and fluffy — about 4–5 minutes with an electric mixer on high, or 8–10 minutes by hand with a whisk. This trapped air is what makes the cake light.

Step 3

Sift the flour over the egg mixture and fold it in gently with a spatula: cut down through the middle, sweep along the bottom of the bowl, and lift the batter over the top, turning the bowl a little each time. Then fold in the melted, slightly cooled butter the same way until just combined — stop as soon as no streaks remain.

Step 4

Add the cinnamon, salt and vanilla extract. Fold in the diced apple until evenly distributed.

Step 5

Pour the batter into the prepared pan and smooth the top. Arrange the thinly sliced apple on top and press lightly. Optionally sprinkle with almond shavings.

Step 6

Bake for 45–50 minutes until a skewer inserted in the center comes out clean.

Step 7

Cool in the pan for a few minutes, then remove and cool completely on a wire rack. Dust with powdered sugar before serving.