Prep your squash and carrots. To peel the squash I cut it into quarters (or smaller if needed) and then peel each piece using a potato peeler. Chop the onion and celery. 

Melt the butter and olive oil on medium heat in a large pot.

Add the onion and celery to the pot, cook for about 5 minutes on medium-high heat, stirring often, until softened.

Add the vegetable broth, water, squash, carrots, Italian seasoning, and garlic powder to the pot.

Bring soup to a boil and then cover it with the lid slightly ajar, and simmer on medium-low heat for about 30 minutes or until the veggies are softened (it may take more or less time depending on how small you chopped them). 

Working in batches, blend the soup until it's smooth. I recommend letting it cool for at least 15 minutes prior to doing this. You could also use a stick blender, but I prefer the results with a regular blender.

Season with salt & pepper to taste and serve immediately. Can be stored in the fridge for several days or frozen for 3 months. I like to serve this soup with snipped fresh chives (optional).