1.      In a large pot, sauté the onion and celery in the olive oil until onions are soft, about 5 minutes. Add in garlic and Italian seasoning and stir for one minute more. Add in the potatoes, carrots & rutabaga (or sweet potato). Stir to combine and add broth.

2.      Bring the soup to a rolling boil then lower the temperature to a simmer. Cover the soup and simmer for 30 minutes, or until the vegetables are tender. Once the vegetables are cooked through, stir in the sour cream.

3.      In a separate, smaller pot, make a roux by melting the butter over medium-high heat. Once the butter is melted, add the flour and whisk constantly for about 1 minute. Slowly start adding in the milk, a little at a time, whisking the mixture the whole time to fully incorporate the flour/butter & milk. Do this until all of the milk is used and the mixture is thick.

4.      Add the roux to the soup slowly, making sure to stir it in well to ensure the roux is fully incorporated into the soup. Lower the temperature of the soup to avoid it burning to the bottom of the pot and let stand for 10 minutes or so. Give it another good stir and serve.