Add 2 tablespoons of butter to a skillet and heat to medium high.
Turn down to medium and saute the onion for about 10 minutes.
Add the mushrooms and cook until their liquid is cooked out of them. About another 10 to 15 minutes.
Add 1 tablespoon and the flour.
Cook 3 minutes until the raw taste of the flour is gone.
Add the broth.
Bring to medium high - stirring once in a while to a mild boil.
Do not let burn.
Turn down the heat to medium and add the coconut milk.
Cook for about 10 minutes.
Add the seasonings.
Let cool for at least 15 minutes. If you try to blend hot ingredients in a blender they will explode everywhere.
Add one third to half of the soup mixture to a blender and blend until creamy.
Pour into a large bowl and set aside.
Continue with the rest of the mushroom mixture until all is creamy.
If serving now add to a large pan and heat through and serve.
Garnish with black pepper, scallion slices and croutons.
You can also refrigerate for a couple of days.