Heat the canola oil in a large soup pot over medium heat.

Add the chopped onions and cook until lightly browned, about 5 minutes.

Add the diced potato, sliced carrots, diced celery, diced turnip, zucchini, and diced tomatoes.

Cook the vegetables, stirring occasionally, for about 15 minutes to develop their flavors.

Pour in the water and add the fresh parsley, bay leaf, and dried thyme.

Bring the mixture to a simmer, then reduce the heat and let it simmer for 45-50 minutes.

Strain the broth through a fine-mesh strainer into a large bowl or container.

Press the vegetables with the back of a spoon to extract as much liquid as possible.

Allow the broth to cool completely before refrigerating until ready to use.