Peel and chop the onion.
Next, peel the carrots and potato and chop into 1 cm pieces.
Cut the courgette or zucchini the same way. There is no need to peel, just wash them and cut of the stalk.
Put the saucepan over a medium heat and add the oil.
Add the onions and cook for about 3 minutes until the onions start to become translucent.
Now add the chopped potatoes, carrots and courgettes and cook for 5 minutes, stirring regularly.
Stir in the flour for a minute theb add the stock and pepper.
Increase the heat, put on the lid and bring the mixture to a simmer.
Cook for about 10 minutes or until all the vegetables are tender.
Allow to cool for a few minutes.
Transfer to a blender and liquidise the soup.
Return the carrot and courgette soup to the saucepan.
Reheat the soup and season to taste.
Chop the basil and add half to the soup. Use the remaining basil as garnish.