Heat the oil in a large skillet or dutch oven. Add the onions and cook for 2 - 3 minutes, stirring often. Add the ginger, garlic and curry powder and cook for another minute.
Once the mixture is starting to be fragrant, add the tomato and red curry pastes. Stir everything together until combined.
Stir in sweet potato and lentils and cook for another 30 seconds before adding the coconut milk. Bring this mixture to a boil then cover and simmer for 15 minutes.
Remove the lid and stir in vegetable broth, then season with salt and pepper. Cover again and cook for another 15 minutes.
Serve warm with rice, quinoa, cauliflower rice, etc., as well as some cilantro. I also love serving this with a side of sauteed spinach or kale!