Before cooking, wash your hands and put on an apron. Weigh and measure all the ingredients. Ask a grown-up to preheat the oven to 220C/425F/Gas 7. Grease a small (500g) loaf tin with a little vegetable oil using a pastry brush.
Place the sugar and butter into a mixing bowl. Using the back of a fork mash the ingredients together until completely combined.
Break the egg into a cup and whisk with a fork. Add the egg to the sugar and butter and stir.
Grate the courgette and add this to the mixture with the flour, mixed spice and lime juice and stir using a wooden spoon.
Put the mixture into the prepared loaf tin. Ask a grown-up to put it in the oven for 20–25 minutes until golden-brown on the top. Serve in slices with some fresh fruit.