Toss the diced pumpkin, chopped onion, minced garlic, and diced carrot with olive oil, salt, and pepper in a large mixing bowl.
Spread the mixture evenly on a baking sheet in a single layer and roast in the preheated oven for 25-30 minutes, or until the pumpkin is tender and slightly caramelized.
Once roasted, transfer the vegetable mixture to a large pot. Add the vegetable broth, ground cumin, and ground ginger.
Bring the mixture to a simmer over medium heat and let it cook for 10 minutes, allowing the flavors to meld together.
Remove the pot from heat and use an immersion blender (or a regular blender in batches) to puree the soup until smooth.
Return the soup to low heat, stir in the coconut milk, and adjust seasoning with more salt and pepper if needed.
Serve hot, garnished with fresh cilantro or parsley.