Place carrots in a large bowl and drizzle one tablespoon of the olive oil over the top. Toss to coat and add 1/2 teaspoon salt and 1/4 teaspoon pepper. Toss again. Spread in a single layer on a rimmed cookie sheet and bake, stirring/flipping every 15 minutes or so, until tender and browned in spots, about 40 minutes total. Remove from oven and let cool a bit.
While the carrots are cooking, heat the remaining tablespoon of olive oil in a large soup pot over medium-low heat. Add the onions and cook until just beginning to brown, about 8 – 10 minutes. Add the ginger and the vegetable broth and bring to a boil. Reduce heat, cover, and let simmer for five minutes until ginger is tender. Remove from heat.
When both the roasted carrots and the broth have cooled somewhat, add the carrots to the broth. Working with a blender in batches, puree the soup and return it to the pot; or use an immersion blender directly in the pot. Please make sure your soup has cooled enough to safely puree!
Place pureed soup over medium heat and return to a simmer. Reduce heat to low and stir in the heavy whipping cream. Taste and add additional salt and pepper if desired. Serve.