Place a large saucepan over medium heat. Add the olive oil and butter and let it melt. Add the leek and cook, stirring, for 2–3 minutes. Then add the bacon and stir through for about 2 minutes. Add the celery, carrot, potato and zucchini. Stir through and cook for about 10 minutes, until soft and fragrant.
1 tbsp extra virgin olive oil, 1 tbsp butter, 1 leek, 5 bacon rashers, 3 celery sticks, 2 carrots, 2 potatoes, 2 zucchini