In a 4- to 5- quart Dutch oven cook onion, sweet pepper, and lentils in hot oil over medium-high heat for 2 minutes. Whisk in ginger, curry powder, cumin, stock, and pumpkin puree. Bring to boiling; reduce heat to medium-low. Simmer, covered, for 25 minutes or until lentils are tender, stirring occasionally. Season to taste with salt and pepper.
To serve, ladle into bowls and sprinkle with grated nutmeg and flat leaf parsley.