Saffron Flavored Pumpkin Soup

Ingredients:

1 Kabocha squash, approximately 4 pounds
2 leaks, trimmed
3-4 cups of milk
1/4 cup of flour
4 tablespoons of butter
1 teaspoon of salt
1/2 teaspoon of white pepper
1/4 teaspoon of ginger powder
A large pinch of saffron
1 whole nutmeg