First off, heat the butter in a large pot, and sauté the onion, garlic, celery and leeks until translucent.
Add the tins of tomatoes, stock and puree and mix through.
Add the vegetables, season and bring to a boil. Simmer for 40 minutes covered.
I chopped my veggies quite fine for this recipe, but you can keep them in larger chunks, or just mash the cooked veg until you have the desired thickness.
Serve with fresh zucchini noodles and baby herb leaves.