Step 1. Preheat the Oven and Prepare the Pan

Preheat your oven to 180°C (350°F). Grease and line a 9-inch square baking pan with parchment paper.

Step 2. Combine Dry Ingredients

In a mixing bowl, sift together the self-raising flour, caster sugar, baking powder, and ground cinnamon. Stir to combine.

Step 3. Rub in the Butter

Add the softened butter to the dry ingredients. Using your fingertips, rub the butter into the flour mixture until it resembles breadcrumbs.

Step 4. Add Wet Ingredients

In a separate bowl, whisk the eggs and milk together, then pour them into the flour and butter mixture. Stir gently until just combined to create a smooth batter.

Step 5. Layer the Batter and Apples

Pour half of the batter into the prepared baking pan and spread it evenly. Arrange a layer of apple slices over the batter, then spread the remaining batter on top, covering the apples. Arrange more apple slices on the top layer, pressing them slightly into the batter.

Step 6. Sprinkle with Demerara Sugar (Optional)

For a crunchy top, sprinkle the Demerara sugar over the top layer of apples.

Step 7. Bake the Cake

Bake in the preheated oven for 40-45 minutes, or until a skewer inserted into the center of the cake comes out clean. The top should be golden brown.

Step 8. Cool and Serve

Allow the cake to cool in the pan for 10 minutes, then transfer it to a wire rack to cool completely. Slice and serve on its own or with whipped cream or ice cream.