Preheat your oven to 180°C. Line your cake tin with baking paper. Lightly grease the sides with butter. This helps the cake release easily after baking and keeps its shape nice and clean.

Place butter and sugar in a bowl. Beat them until light and fluffy. This step adds air into the mixture. It helps create a soft and tender cake texture.

Add eggs one at a time. Mix well after each addition. Then add vanilla extract. Keep mixing until the batter looks smooth and creamy without lumps.

In a separate bowl, combine flour, baking powder and salt. Stir gently so everything blends evenly. This step helps the cake rise properly in the oven.

Slowly add the dry mix into the wet mixture. Stir gently using a spatula. Add milk to loosen the batter. Do not overmix or the cake may become heavy.

Add the sliced apples into the batter. Fold them gently so they spread evenly. This gives soft fruit pieces in every bite of the cake.

Pour half the batter into the cake tin. Add spoonfuls of lemon curd on top. Then add remaining batter. Swirl lightly with a knife for a marbled effect.

Place the cake in the oven. Bake for 40–45 minutes. Check with a toothpick in the center. If it comes out clean, the cake is ready.

Let the cake cool in the tin for 10 minutes. Then transfer it to a rack. Dust with powdered sugar before serving. Enjoy it warm or at room temperature.