Rinse the red lentils thoroughly under cold water and drain.
Heat the olive oil in a large pot or Dutch oven over medium heat.
Add the chopped onion and sauté until translucent, about 5 minutes.
Stir in the minced garlic and grated ginger, cooking for an additional 1-2 minutes until fragrant.
Add the diced sweet potatoes, curry powder, turmeric, and cumin seeds to the pot. Stir well to combine and cook for another 5 minutes.
Pour in the vegetable broth and coconut milk, then add the rinsed lentils. Stir everything together.
Bring the mixture to a boil, then reduce the heat to low and cover the pot.
Let it simmer for about 20-25 minutes, or until the lentils and sweet potatoes are tender. Stir occasionally to prevent sticking.
Season with salt to taste and cook for another 2 minutes.
Remove from heat and let sit for a few minutes. Garnish with fresh cilantro if desired.
Serve warm in bowls with rice or bread as preferred.