Peel and chop the apples then mix the lemon juice into the chopped apple so it doesn't go brown
Mix the brown sugar and cinnamon together and leave till later.
Beat the butter and caster sugar together until light and creamy. Beat in the eggs one at a time and then the vanilla.
Mix the flour and baking powder together then sift them into the bowl with the egg mixture. Stir in gently until fully incorporated. Mix in the milk until smooth.
Put a quarter of the mixture into each tin. Sprinkle on a layer of apple then add the rest of the cake mixture. Top with the rest of the apple and the cinnamon sugar mixture.
Bake the cakes for about 40-50 minutes at 160C.
Test they are ready by inserting a skewer which should come out clean.
Turn the cakes out of the tins and leave them to cool on a wire rack.
Spread a layer of caramel on one of the cakes.
Make the buttercream by beating together all the buttercream ingredients. Spread the buttercream on top of the caramel. Top with the second cake.
Heat some of the caramel in a bowl in the microwave. Drizzle it over the top of the cake.
Notes
Nutritional information is approximate and a guideline only.