Pour olive oil in a pot ( notice I did not use butter) , you can if you prefer butter over olive oil and cook the onions until lightly browned. Add the squash and transfer the mix to a blender ( I used Vitamix).
Add whole milk, water and chipotle pepper to the blender . Blend till you the desired consistency is achieved. Then transfer the mix to the pot. Add salt and black pepper. Warm it up furthur and serve hot.