Dice the onion, mince the garlic, and grate the ginger (use a small hole cheese grater). Sauté the onion, garlic, and ginger in a large pot with the olive oil over medium heat until the onions are soft and transparent.
Add the pumpkin purée, red lentils, broth, and curry powder. Stir to combine.
Place a lid on the pot, turn the heat up to medium-high, and allow it to come to a boil. Once it reaches a boil, turn the heat down and simmer on low for 20 minutes, stirring occasionally. After 20 minutes the lentils should be soft and the soup slightly thickened.
Taste to adjust the curry powder or salt as needed, then serve.