Step 1

Turn on the oven to 180 degrees Celsius (160 degrees fan/gas) 4.

Step 2

Prepare a 20-centimeter/8-inch springform pan by greasing and lining the bottom with silicone paper.

Step 3

Whip the butter, vanilla, and caster sugar together until frothy. Gently beat in each egg, ensuring that each one is well mixed before adding the next.

Step 4

Carefully avoid overmixing after adding the flour and stirring to get a smooth batter.

Step 5

Slot the apple wedges onto the top of the mix; it’s okay if they appear a little overloaded; the apples will shrink while baking.

Step 6

Sprinkle with a mixture of demerara sugar and cinnamon.

Step 7

Bake for approximately 1 hour (check after 50 minutes) or until a skewer inserted in the center of the cake comes out clean and the sponge is risen and golden.

Step 8

Cool in the tin for 10 minutes, then transfer to a wire rack to cool fully.

Step 9

Sprinkle with powdered sugar (optional).