In a large saucepan, combine all of the ingredients except the milks and the flour. Cover and bring to a boil. Allow the vegetables to cook until they are soft, around 25-30 minutes.
In a medium bowl, mix together the milks and the flour until combined. Add to the saucepan, and cook until the soup has thickened, around 5 minutes.
Remove from heat and blend with an immersion blender, or transfer batches to a blender and mix until smooth.
Divide into bowls, and garnish with additional coconut milk, if desired.