In a bowl, mix together the onion, cauliflower, squash cubes, 1 1/2 tsp.
olive oil, rosemary, salt and pepper.
Transfer to a paper-covered baking sheet with parchment roast in the oven for 45 to 60 minutes, or until squash is tender, turning the vegetables after 30 minutes.
In a pan, add 1 1/2 tsp.olive oil, and cook the garlic for 1 minute over medium heat, stirring constantly.
Add roasted vegetables (keep some pieces of roasted cauliflower for garnish, if desired)and chicken broth.
Bring the mixture to a boil and cover.
Reduce heat to low and simmer for 15 minutes.
In a blender or food processor, process until smooth.
Return the soup to the pan.
Add milk and mix with a wooden spoon.
Warm over medium heat without boiling.
For a smoother soup, add a little more milk.
Garnish with finely chopped parsley, roasted cauliflower and a drizzle of extra-virgin olive oil.