Sauté the aromatics: Heat olive oil in a large pot over medium heat. Add the chopped onions and fry for 3 to 4 minutes until softened.
Add ginger and garlic: Stir in the chopped ginger and cook for 2 to 3 minutes. Add the garlic and cook for another 2 minutes until fragrant.
Toast the spice: Add 1 tsp of turmeric, stirring constantly for about a minute to release its flavor.
Simmer the sweet potatoes: Add the chopped sweet potatoes to the pot. Pour in just enough hot water to cover the sweet potatoes (start light to keep the soup creamy; you can thin it out later). Stir in 1 tbsp of vegetable broth powder. Bring to a gentle boil on medium heat for about 15 minutes, or until the sweet potatoes are fork-tender.
Blend: Turn off the heat and pour in the coconut milk. Use an immersion blender to puree the soup until completely smooth and creamy. Adjust with a splash of extra hot water if a thinner consistency is preferred.
Garnish & Serve: Stir in optional chickpeas or fried tofu if desired. Ladle into bowls, top with fresh cilantro, and serve warm.