Preheat the oven to 400 degrees Fahrenheit. Line a large rimmed baking sheet with parchment paper for easy cleanup, if desired.
To prepare your carrots, peel them and cut them on the diagonal so each piece is about ½″ thick at the widest part.
Place the carrots on the baking sheet. Add 2 tablespoons olive oil and ½ teaspoon of the salt. Toss until the carrots are lightly coated in oil and seasonings. Arrange them in a single layer.
Roast the carrots until they’re caramelized on the edges and easily pierced through by a fork, 35- 40 minutes.
Once the carrots are almost done roasting, in a soup pot, warm the remaining 2 tablespoon olive oil over medium heat until shimmering. Add the onion and ¼ teaspoon salt. Cook, stirring occasionally, until the onion is softened and turning translucent, 5 to 7 minutes.
Add the garlic, ginger, curry coriander and cumin. Cook until fragrant while stirring constantly, about 30 seconds to 1 minute. Pour in the vegetable broth and water, while scraping up any browned bits on the bottom with a spoon.
Add the roasted carrots to the pot when they are out of the oven. Bring the mixture to a boil over high heat, then reduce the heat as necessary to maintain a gentle simmer. Cook for 15 minutes, to give the flavors time to meld.
Remove the pot from the heat and let it cool for a few minutes. Blend with an immersion blender until smooth and creamy. Stir in the coconut milk.
