Cut onions into eighths. Heat pumpkin seed oil and butter, sauté onions. Add the lentils. Extinguish with soup, bring to a boil and simmer with closed lid at low temperature for 50 minutes until tender.
Season soup with pepper, coriander and thyme.
Chop parsley. Grind the soup. Stir in about 3/4 of the sour cream and the parsley. Season with salt, simmer for 5 minutes.
Roast pumpkin seeds without adding fat until they are intensely fragrant. Sprinkle seeds and grated cheese into the soup. Garnish with the remaining sour cream.