Preheat the oven to 180°C. Grease then line a 28 x 20cm tin

Melt the butter in a medium fry pan over a medium heat. Add the onion and cook for 4-5 minutes or until the onion softens and starts to smell yummy! Transfer into a large bowl to cool

Once cooled, add all the other ingredients to the bowl. Use a big wooden spoon to mix everything together. Pour the mixture into the tin

Ask Mum or Dad to transfer the tin into the oven to bake for 30 minutes or until the bake has puffed up and is golden. Remove from the oven and cool for five minutes before cutting into eight big squares

Eat straight away or refrigerate it then pack it in your lunchbox with an ice brick to enjoy at school