Preheat oven to 400 degrees Fahrenheit. Place chopped celery, the white part s of the leeks, garlic, potato, onion, and carrots on a baking sheet and coat with oil. Bake till lightly browned and fork tender, about 45 minutes.

Transfer roasted veggies to a large pot and add the green parts of the leeks, celery leaves, mushrooms, water, and bay leaves. Bring to a covered boil, reduce to a simmer, and cook cover for an hour.

Then strain the broth and let it cool. Once cooled, transfer to jars and store in the refrigerator. Use broth in soups, risotto, to cook quinoa, or anything else and enjoy!