Step 1. Preheat the Oven and Prepare the Baking Tray

Preheat your oven to 180°C (350°F). Grease a 9×13-inch baking tray and line it with parchment paper for easy removal.

Step 2. Cream Butter and Sugar

In a mixing bowl, beat the softened butter and caster sugar together until light and fluffy, about 2-3 minutes.

Step 3. Add Eggs and Vanilla

Add the eggs one at a time, beating well after each addition. Mix in the vanilla extract until fully incorporated.

Step 4. Add the Dry Ingredients

Sift the self-raising flour and baking powder into the bowl. Gently fold the flour mixture into the wet ingredients until just combined. Be careful not to overmix to keep the cake light and airy.

Step 5. Add the Apples

Fold in the thinly sliced apples and ground cinnamon (if using) until the apples are evenly distributed in the batter.

Step 6. Pour the Batter and Spread Evenly

Pour the batter into the prepared baking tray and spread it out evenly with a spatula.

Step 7. Bake the Traybake

Bake in the preheated oven for 35-40 minutes, or until a skewer inserted into the center comes out clean and the top is golden brown.

Step 8. Cool and Dust with Powdered Sugar

Allow the cake to cool in the tray for 10 minutes, then transfer it to a wire rack to cool completely. Once cooled, dust with powdered sugar for a decorative finish, if desired.

Step 9. Slice and Serve

Cut the traybake into squares and serve plain, or with a dollop of whipped cream or a scoop of vanilla ice cream.