Pre-heat your oven to 160C Fan/180C/350F/Gas Mark 4, and grease and line a 12" x 9" traybake tin
To make the sponge, mix together the butter and light brown sugar until smooth, ideally using an electric mixer
Then whisk in the eggs. Then mix in the apple using a spatula
Then gently whisk in the self raising flour, cinnamon and mixed spice
Pour the mixture into the tin and bake for 25-30 minutes or until a skewer inserted in the centre comes out clean. Leave to cool fully
To make the butercream use an electric hand whisk to mix together the butter and icing sugar, when they start to come together, add the caramel extract and mix until smooth. If the buttercream is too stiff then you can add some milk to it
Spread the frosting on top of the sponge, then drizzle over the caramel sauce
To serve, slice into squares. Store any leftovers in the fridge and eat within 3 days
Notes
Make sure all your ingredients (particularly the butter and eggs) are at room temperature before you start baking.
I used unsalted butter for the buttercream, for the cake I used a baking spread.
Mixed spice is a British spice blend containing cinnamon, coriander seed, nutmeg, clove, pimento and ginger. If you can't get hold of it, you can use a mix of ginger, nutmeg and cinnamon, or use a Pumpkin Spice mix instead.
I really recommend using light brown soft sugar if you can, as it gives the cake a lovely caramel flavour. But if you can't get hold of it, you can use golden caster sugar or regular caster sugar (superfine sugar) instead.
If you can’t get caramel extract, add 75g caramel sauce to the buttercream instead.
Although I provide cup measurements, I highly recommend weighing your ingredients out using digital kitchen scales*. It is the most accurate way to measure ingredients and will ensure the best results. Digital scales are very low cost and can be purchased for around £12 ($16.50) .
For teaspoon (tsp) and tablespoon (tbsp) measurements, please use measuring spoons* and not the type of spoons you eat with. Again this will ensure accuracy and provide the best results.