Preheat oven to 400 degrees and line a baking sheet with parchment or a silicone baking mat.
Toss diced carrots and onion with olive oil, salt, pepper, ginger, garlic, parsley and lemon juice. Be sure all of the vegetables are lightly coated in oil. If not, add a bit more oil. Spread onto a lined baking sheet and roast for about 30 minutes or until softened.
Place the roasted vegetables into a sauce pan with broth and water, bringing to a boil and reducing to a simmer for about 10 minutes. We want those vegetables very, very tender.
Cool this mixture slightly and place into a food processor, pureeing until smooth. Do this in batches.
Serve with a dollop of vegan sour cream and garnish with a sprig of fresh parsley.