Mashed Cauliflower and Acorn Squash

1 small cauliflower
1 small acorn squash, seeded
1 small red onion
¼ cup olive oil
3 or 4 cloves garlic, or 2 tsp ground garlic
2 tsp basil
1 tsp kosher or sea salt
½ tsp pepper
2 cups water
Preheat the oven to 400°F/200°C . Cover a large baking pan with foil. Cut acorn squash into quarters (with skin), cauliflower, and onion into quarters and toss in a large bowl with the oil, garlic, basil, salt, and pepper. Spread out on the baking pan and roast for about 45 minutes uncovered until soft and slightly browned.Remove from the oven and let the vegetables cool. Then blend with water in a large food processor or blender until creamy and smooth. Add additional water to make this into a filling soup. Season to taste, sprinkle with dehydrated onion and chopped parsley. Sometimes I reserve some of the roasted onion and chop it up to garnish the top.