Preheat the oven to 180°C (350°F). Grease and flour a 9-inch round cake pan.

In a mixing bowl, cream together the softened butter and granulated sugar until light and fluffy.

Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.

In another bowl, whisk together the flour, baking powder, and salt. Gradually add to the butter mixture, mixing until just combined.

In a separate bowl, combine the sliced apples, brown sugar, cinnamon, and lemon juice. Toss until the apples are well coated.

Pour half of the cake batter into the prepared pan. Layer the apple filling on top, then pour the remaining batter over the apples.

Bake in the preheated oven for 40-45 minutes, or until a toothpick inserted into the center comes out clean.

Allow to cool in the pan for 10 minutes before transferring to a wire rack to cool completely.