Creamy Butternut Squash and Celery Root Soup

1 large butternut squash, peeled and cut into chunks
1 celery root, peeled and cut into chunks
1 - 2 green apples, peeled, cored and cut into chunks
3 carrots, chopped into thin coins
2 onions or leeks (or both!), chopped coarsely
olive oil
2 cups veggie stock - optional
cream - optional and to taste
salt and pepper
homemade croutons - optional
dill or chives - optional
Saute the onions or leeks in a large soup pot with some olive oil. Add the butternut, celery root, carrots, apples and veggie stock to the pot. Add enough water to cover the veggies by an inch. Boil this mixture until all the veggies are very, very soft. Blend all of it with an immersion blender or in a regular blender in batches until super smooth. Add the cream and stir to combine, if using. Season with salt and pepper. After the soup is served in the bowls, top with a few homemade croutons and some bright herbs, such as dill or chives.