Lightly grease the inside of the inner pan with butter or spray oil and set aside.
In a large bowl combine the butter, brown sugar, ground cinnamon and vanilla. Add the apple slices and thoroughly stir to coat the apple slices.
Arrange the apple slices evenly, overlapping, over the base of the inner pan. Pour over any extra butter mixture.
Place the flour, baking powder and cinnamon into a large bowl and stir to combine.
In a medium size bowl, whisk together the melted butter, vegetable oil, vanilla extract, eggs, and caster sugar.
Add the egg mixture to the flour mixture and mix together with a spatula until all the flour is incorporated. Pour the mixture over the apples and smooth the surface.
Place the inner pan into the rice cooker and close the lid.
Select the 'Cake/Bread' setting and dial in 35 minutes.
When the cake is ready, remove the inner pan from the rice cooker and allow to sit for 5 minutes. Place a plate over the top of the inner pan and flip the cake out.