Coat the bottom of a large pot with the oil and place it over medium heat. Give the oil a minute to heat up, then add the onion. Sweat the onion for about 5 minutes, stirring occasionally, until it begins to soften up.
Stir in the garlic, ginger, cumin, coriander, cinnamon, and cardamom. Cook the mixture for about 1 minute, stirring constantly, until it becomes very fragrant.
Stir in the broth, carrots and sweet potato. Raise the heat to high and bring the broth to a boil, then lower the heat and let the stew cook at a simmer for about 20 minutes, until the carrots and sweet potato are soft.
Blend the stew. You can either do this using an immersion blender, or by carefully transferring it to a food processor or blender in batches. Always be careful when blending hot liquids.
Return the stew to the pot if you removed it, then stir in the orange juice. You can also thin the stew with additional broth or water at this point, if you'd like (although I prefer it thick). Stir in the brown sugar, sriracha sauce, and salt.
Heat the stew back up for a few minutes if it has cooled down too much.
Ladle the stew into bowls, and to each with a sprinkle of fresh cilantro and peanuts before serving.