In thick bottomed medium sized saucepan, sauté:
While mixture is sautéing, puree in a blender:
Add puree to saucepan with:
Simmer soup for 30 minutes. Take off heat, remove lemongrass stalks, and put soup in a bowl or other large container vessel. Soup needs to be pureed before next step. Use an immersion blender or blend in small batches.
In now empty saucepan, make a roux:
Whisk it in and let thicken, then repeat process with another 2 cups until all soup is added. It is important to gradually add soup puree to roux and let soup thicken slowly in between every addition.
Notes from Sarah:
There are several steps to this recipe. Basically, the soup is made, pureed, added to a roux, slowly thickened, and finished off with coconut milk.
This recipe is from Sarah Gordon of Tamales Especiales and Revolution In The Kitchen http://www.revolutioninthe.kitchen/