Heat the oil in a large saucepan over medium heat. Add the garlic, onion, ¼ teaspoon of salt and 1/8 teaspoon of pepper and saute for about 5 minutes, until the onion is soft and translucent.
Add the celery, carrot, zucchini, squash, and bell pepper and saute for 5 minutes more, stirring occasionally. Stir in the fresh tomatoes, the canned tomatoes and their juice, the tomato paste, and the herbs. Add the vegetable broth, increase the heat to high, and bring just to a boil. Reduce the heat to medium and simmer, uncovered, for 15 minutes.
Season with ¼ teaspoon of salt and 1/8 teaspoon of pepper and simmer for 15 minutes more. Remove the saucepan from the heat and allow the sauce to cool slightly. Pour the sauce into your blender in batches and puree on high for 1 to 2 minutes, until creamy. (Remember to remove the plastic cap in the blender top and cover the opening with a kitchen towel so steam can escape while you blend.) Season with salt and pepper to taste. Store this in an airtight container in the fridge for up to 1 week, or in the freezer for up to 3 months.