In a soup pot, melt butter, add the flour and stir over medium heat for 3 minutes. Mix in the onions and cook for 2 more minutes.
Whisk in the chicken stock. Add pumpkin pieces and simmer for 20 minutes.
Add bay leaf, saffron, lemon juice, nutmeg, salt and pepper.
Puree soup in a blender. Stir in the light cream and butter. Serve hot.