Heat a medium stock pot over medium-high heat. Once hot, add olive oil and heat. Add onion, garlic, squash, apples, salt, cinnamon and sage. Saute for 10-12 minutes, stirring occasionally, until onions are translucent. Add the stock and stir to incorporate. Simmer over medium-low heat for 1½ hours. Place the immersion blender into the middle of the stockpot. Submerge the blender below the surface of the liquid, but above the bottom of the pot. Start the blender on its lowest speed, and increase as desired. Move the immersion blender around, including up and down, to blend the ingredients for approximately 1-2 minutes or until desired consistency is achieved. Serve immediately, or cool in an ice bath and store in an airtight container in the refrigerator.