Butternut Squash Soup with Spinach and Mushrooms

1 medium butternut squash, peeled, seeded, and chopped
2 cups mushrooms, chopped
1 Vidalia onion, diced
3 cloves garlic, minced
1 quart vegetable broth
olive oil
Several handfuls of fresh spinach

Salt and Pepper to taste
Peel squash and cut in half lengthwise. Remove seeds and chop into small cubes. The smaller you chop, the faster it will cook. Sauté onions and mushrooms in olive oil. Set aside. Sauté butternut squash and garlic until soft. Add vegetable broth and bring soup to a simmer. Remove from heat and use an immersion blender to cream the soup. Blend until completely smooth. Stir in the sautéed onions and mushrooms and also the spinach. Salt and pepper to taste.