Preheat the oven to 170ºC and grease a muffin tin with butter or non-stick cooking spray and dust lightly with flour.
In a medium bowl, mix the olive oil, sugar, lemon zest, vanilla and egg.
Grate the courgette using the medium side of a cheese grater. Squeeze the excess water out of the courgettes over the sink and add to the bowl. Mix the ingredients well. A wooden spoon is all you need.
Mix in the dry ingredients- the flour, salt, baking powder and bicarb of soda. No need to sift everything together.
Pour the muffin mix between the cups of the muffin tin. Each cup should weigh between 75-85g.
Bake in the preheated oven for 15 minutes and check them. My oven runs a little on the cool side so I had to add an extra 8 minutes. Check the muffins after 15 minutes. If they need more time, keep checking after every 5 minutes. When the muffins are fully baked take them out and leave them to cool for about 5 minutes in the tin before turning them out to finish cooling on a wire rack.