To make the sponge:
- First turn on your fan oven to 170℃
- Put the 200 g flour, 200 g sugar, 4 eggs and 200 g olive oil into a food mixer and mix for a couple of minutes until you get a smooth batter. While still mixing, add a few drops of yellow food colouring until you achieve the desired colour, the same as a washing up sponge. Make sure you keep mixing to ensure all the batter takes on the colour.
- Transfer to a parchment lined baking tin measuring 8 cm by 10 cm and bake for 20-22 minutes. Pierce the centre with a skewer to check it is cooked (the skewer should come out clean if it is cooked. If not quite baked, return to the oven for a couple minutes until done).
- Leave to cool for 2 hours. While it is cooling, you can make the rest of your components.
To make the scourer top:
- Leave your oven on at the same temperature.
- Mix the flour, sugar, oil, lime zest and eggs in your food mixer until you get a smooth batter. While still mixing, add your green food colouring gel drop by drop until you get a dark green colour, similar to the top of a scourer.
- Spread this mix onto a parchment lined baking tray (you dont need to be neat as it's going to get crumbed anyway).
- Bake for around 5 minutes or until cooked, it wont take long.
- Leave to cool alongside your yellow sponge.
To make the lemon foam:
- Put the cold sugar syrup, water, lemon juice and soya lecithin into a deep bowl and blitz with a stick blender for 2 minutes, until the soya lecithin has dissolved.
- Transfer to a long, flattish tupperware, cover with clingfilm and put in the fridge until needed. It needs to be as cold as possible to make a good foam.
To make the apple coulis:
- Turn your oven up to 190℃
- Bake the half apple as it is for 30 minutes.
- Remove from the oven and leave to cool for around 30 minutes.
- Chop up the remaining whole apple and then blend with the cooked apple, the sugar, water and lemon juice.
- Pass through a fine sieve
- Whisk a few drops of light green food colouring into your puree, until it looks like washing up liquid, then chill until needed.
To construct the sponge:
- Take your green lime sponge and blitz in a food processor until you get a fine crumb.
- Take your yellow sponge and trim a bit off each side and the top and bottom so you have a large, uniform rectangle.
- Divide into 8 by cutting in half lengthways, then 3 times width ways ( you should have 8 small rectangles).
- Top each with a layer of green crumb roughly 3mm thick and compress firmly to make dense. Trim the edges to make neat and roughen the green side a little.
- Place one of your sponges on a plate, green side up.
- Add a spoonful of apple coulis on top, allowing some to run down the side. A squeezy bottle would be ideal.
- Finally, take your lemon foam out the fridge and peel back one corner of the cling film.
- Place your stick blender in, cover back with cling film and whizz for a minute. You should be producing foam on the surface.
- Spoon some off and place on top of your sponge cake.