1. Preheat the oven to 180°C/350°F/Gas Mark 4. Grease a 1.2L loaf tin with the oil, then line with baking parchment. I usually put a strip along the whole length of the tin, making sure it comes well over the edges. This makes it easy to remove the loaf when it’s cooled.
2. Place the grated courgettes in a tea towel and wring out as much of the moisture as you can over the sink. This can take a few minutes but is an important step because if the courgettes are too wet, the loaf may become too soggy.

3. Melt the butter in a pan, and then put it in a bowl along with the sugar. Add the courgettes to the bowl along with the lemon zest, pistachios, vanilla and eggs, and mix this together until combined. Then add the gluten free flour, the baking powder and the salt, and carefully fold in.
4. Tip the mixture into the lined tin and bake for 50 minutes or until a skewer inserted into the centre of the loaf comes out clean.

5. Once the loaf is baked, remove it from the oven and set aside whilst you make a drizzle. To make the drizzle, mix the lemon juice and the icing sugar together. Using a fork or toothpick, gently prick the top of the loaf and then pour the drizzle all over the cake so that some soaks into the loaf and the rest forms a light glaze on the top.

6. Remove the loaf from the tin, sprinkle the remaining pistachios over the loaf and serve.